MGC-Bulletin, Nr. 49, September 2013 In dit nummer

MEDISCH-GENETISCH CENTRUM ZUID-WEST NEDERLAND - MGC

Het Centrum is een initiatief van het Universitair Medisch Centrum Rotterdam en het

Leids Universitair Medisch Centrum

MGC-Bulletin, Nr. 49, September 2013

In dit nummer:

Lintjesregen voor Jan Hoeijmakers en Frank Grosveld

PPhhDD TTeeaacchhiinngg PPrrooggrraammmmee CCoommmmiitttteeee .................... 44

MMGGCC PPrroommoovveennddii WWoorrkksshhoopp 22001144 ................................ 44

PPrroommoottiieess ................................................................................................................ 44

NNiieeuuwwee mmeeddeewweerrkkeerrss .......................................................................... 55

LLeezziinnggeenn//ssyymmppoossiiaa ................................................................................ 66

SSeeccttiiee ''DDNNAA hheerrsstteell--mmeecchhaanniissmmeenn'' .............................. 66

SSeeccttiiee ‘‘LLyyssoossoommaall SSttoorraaggee DDiisseeaasseess’’ ...................... 66

VVeerrkkrreeggeenn ssuubbssiiddiieess ............................................................................ 77

PPeerrssoonnaalliiaa//PPrriijjzzeenn ...................................................................................... 77

MMGGCC--BBuulllleettiinn nnoo.. 5500 .............................................................................. 88

PPrrooggrraamm 2233rrdd MMGGCC SSyymmppoossiiuumm .......................................... 99

AAbbssttrraaccttss 2233rrdd MMGGCC SSyymmppoossiiuumm .................................... 1100

DDee MMGGCC bbeessttuuuurrddeerrss eenn hhuunn iinnssttiittuutteenn .............. 1199

AAnnddeerree iinnssttiittuutteenn//ggrrooeeppeenn bbiinnnneenn hheett MMGGCC 1199

HHeett MMGGCC sseeccrreettaarriiaaaatt ........................................................................ 1199

Coördinatie en redactie: M. Nivard/I. Braxhoven e-mail: [email protected] : 071-5269605/69601

mailto:[email protected]

MGC-Bulletin no. 49; September 2013 2

Onderwijs voor promovendi Het aanbod van cursussen voor promovendi in het LUMC is tegenwoordig online beschikbaar. Deze informatie is te vinden op http://intranet.lumc.nl/kwo/scholing.htm. A course on "Scripting for life science researchers” will be given 21 – 23 October in Leiden. This course is designed for researchers, including PhD students and postdocs, who frequently handle large datasets or large numbers of files (images, sequence reads, mass spectra etc.) and who needs a more efficient way of working with such data. The course is equally suitable for those working with Windows, Mac OS X or Linux. No prior knowledge of operating systems is needed, the course includes an optional introduction to Linux and an installation practical for Windows and Mac OS X users. The goal of the course is to empower students and researchers with backgrounds in biology or biomedicine to navigate, manage and perform operations on files and data and metadata in tabular text formats. The data may be microscopy images, FASTA sequences, gene ontology files, chromatograms, mass spectra or tables with data on genes or proteins. The course is not a general introduction to programming and will not deal with XML data, Web services or more advanced topics. The course will be taught by Jeroen Laros, Magnus Palmblad, Rob Marissen, Michiel van Galen and Michel Villerius. We only have facilities to accommodate 16 participants. If more than 16 people register a selection will be madeFor more information and registration see www.medgencentre.nl Erasmus Optical Imaging Centre- OIC organizes the course "Live Cell and Super Resolution Imaging" from November 4-8 in Rotterdam. Topics are: Time lapse, FRAP, FRET, super resolution, single molecule localization, PALM, STORM,

GSDIM, Fluorescent proteins, quantitative data analysis. The course is designed for PhD’s, Postdocs, anyone interested from Molmed, MGC and ONWAR. For registration and program information see http://www.erasmusmc.nl/oic/ The course "Development, stem cells and Disease" will be given in the form of a series of seminar starting Autumn 2013. The aim of this course is to discuss recent advances in our knowledge concerning the molecular and cellular mechanisms controlling the development of vertebrate embryos. Stem cells: embryonic: somatic; cancer plant. Patterning: fluorescence tagging; axis formation; face and limbs. Gene regulation: X-chromosome inactivation, tissue specific regulation. Signalling: Hedgehog, TGFβ, Notch, Wnt signaling. Organ systems: Lung development; sex determination, muscle development, hematopoiesis, neuronal development, Axon-Glia interaction; Axon pathfinding. For more info see www.medgencentre.nl A course on "Safely working in the lab” will be given on December 12th (English version) in Leiden. The following points will be addressed: safe microbiological techniques; radionuclides; carcinogenic agents; blood, viruses; radiation. The course is also open for other new personal of the MGC. The course will be given twice a year depending on the interest in collaboration with the Department VSM of the LUMC. Apply through the MGC web site: www.medgencentre.nl or for people from the LUMC via ‘bedrijfsopleidingen’. A course on " Next generation Sequence data analysis" will be given in January 2014. This course aims at PhD students, postdocs and senior researchers who are interested in planning of already working

http://intranet.lumc.nl/kwo/scholing.htm

http://www.medgencentre.nl/

http://www.erasmusmc.nl/oic/




with next-generation sequencing. Currently available technologies as well as hardware and software solutions will be presented and discussed. The focus of the course will be on data and ways to analyse the data. There is a maximum of 60 places. More information and preregistration: www.medgencentre.nl From our sister school Molecular Medicine the following courses are available: A "Adobe Photoshop, Illustrator &

InDesign Workhop" will be given 24-25 September, a hands-on half-day work-shop. On the 24th you will learn how to use Photoshop and Illustrator for image manipulation for scientific articles and posters. On the 25th you will learn how to apply InDesign for making your posters of a thesis booklet.

"Translational Imaging Wokshop by AMIE: from mouse to man" will be given from 24 – 27 September. The AMIE program provides a platform for scientists interested in imaging technology and molecular imaging in general. The aim is to give a broad introduction into preclinical and translational Molecular imaging techniques and their applications in biology and medicine.

A course on "Biomedical Research Techniques XII", given from 14 – 18 October. This is a popular Five-day course on several lab techniques. The program covers: Day 1: primers and probes, sequencing, SNP-analysis, methylation. Day 2: RNA, RNA expression arrays, RT PCR, SiRNA, data mining. Day 3: site visit DNA/RNA labs; proteomes, mass spectrometry. Day 4: (morning) cytotoxicity, ELISA & flow cytometry; (afternoon) Microscopy: quantitative confocal microscopy, image analysis, FRET, FRAP & computer modeling. Day 5: AMI, MRI, CT, Nuclear, Optical in vivo, site visit proteomics labs. Though full participation is encouraged, it is possible to only participate in part of the course.

"Research management for PhD students" will be given 16 & 30 October. This course is very good for starting PhD students, as you will learn

certain skills to save yourself many grey hairs and to improve your PhD-project. Four aspects of research management are covered in this course: time management, project management, negotiating skills and yearly reviews. It is an interactive course.

For detailed information & registration info www.molmed.nl

Courses organized by Boerhaave CME: Survival Analysis: 23 – 27 September.

Survival analysis is the study of the distribution of life times, i.e. the times from an initiating event (birth, diagnosis, start of treatment) to some terminal event (relapse, death). It is most prominently (but not only) used in the biomedical sciences. A special feature of survival data is that it takes time to observe the event of interest. As a result for a number of subjects the event is not observed, but instead we know that it has not taken place yet. This phenomenon is called censoring and it requires special statistical methods. This course considers both theoretical backgrounds and practical aspects of the analysis of lifetime data.

Using R in Data Analysis: 20-22 November. R is an environment for statistical computing and graphics. Tis flexibility, allied to the fact that it is open-source and free, have made it an ideal repository for implementations of statistical analysis methods, both classic and new. However, it has a steep learning curve, due partly to its using a command-line type of user interface, rather than the usual pull-down menus of most commonly used statistical packages such as SPSS. This 3-day course aims at helping researchers climb this curve, enabling them to perform basic data analysis and graphic displays at the end of the course, as well as giving a platform from which they can deepen their R knowledge later on if necessary.

For detailed information & registration: www.boerhaavenet.nl


http://www.molmed.nl/

http://www.boerhaavenet.nl/


PhD Teaching Programme Committee Since 2011 the MGC has a newly formed PhD Teaching Programme Committee. Members of the committee are: Raymond Poot and Kerstin Wendt of the Erasmus MC and Dorien Peters, Harry Vrieling and Madeleine Nivard of the LUMC. The committee will focus primarily on evaluation of the existing course program and will advise on new courses or teaching activities. (Contact email address: [email protected]) MGC Promovendi Workshop 2014 The 21st MGC-PhD workshop will be organized May-June, 2014. For more information see www.mgcworkshop.nl . The 2014 organizing committee consists of 11 members. From the Erasmus MC: Imke Mandemaker, Shimriet Zeidler, Yasemin Turkyilmaz, Marti Quevedo and Gosia Grosbart , from the LUMC: Asja Moerkamp, Calinda Dingenouts, Risha Smeding and Svetlana Pasteuning and from Newcastle: Haifa Ali. The MGC-PhD student workshop is a 4-day event organized every year by PhD students for PhD students in collaboration with the Institute of Human Genetics from Newcastle! During this workshop PhD students get the chance to: - exchange knowledge in an informal

and relaxed way, through posters and presentations

- build their own network during social events and free time

The workshop is meant for PhD students who are doing their research in one of the MGC departments. The attendance to the workshop is part of the PhD program and PhD students should attend at least three times during their PhD. Promoties Elnaz Farahbakhshian is op 9 april gepromoveerd in Rotterdam op het proefschrift "Ex vivo expansion of hematopoietic stem cells". Promotor: Prof. F. Grosveld.

Linde Kegel is op 10 april in Rotterdam gepromoveerd op het proefschrift "Role and specificity of Lgi4-Adam22 interactions in peripheral nerve myelination. Promotor: Prof. D. Meijer. Ook Andrea Pop is op 10 april in Rotter-dam gepromoveerd op het proefschrift "Fragile X syndrome: Steps towards therapy". Promotor: Prof. B. Oostra; co-promotor: Dr. R. Willemsen. Willemijn van Eldik is op 25 april gepromoveerd in Leiden op het proefschrift "The role of CHAP in muscle development, heart disease and actin signaling". Promotor: Prof. C. Mummery; co-promotor: Dr. P. Passier. Manisha Singh is op 7 mei in Rotterdam gepromoveerd op het proefschrift "Novel immunotherapeutic approaches to fight metastatic breast cancer". Promotor: Prof. F. Grosveld; co-promotor: Dr. C. Gravekamp (Yale University). Romana Nijman is op 22 mei in Rotterdam gepromoveerd op het proefschrift "The impact of the circadian clock on toxic and carcinogenic responses: It's about time!. Promotor: Prof. G. van der Horst. Vanessa French is op 19 juni in Rotterdam gepromoveerd op het proefschrift "Animal models in cardiovascular malformations". Promotor: Prof. B. Oostra; co-promotor: Dr. A. Bertoli-Avella. Jessica Zuin is op 25 juni in Rotterdam gepromoveerd op het proefschrift "Keep in touch; the role of cohesin and CTCF in organizing the human genome". Promotor: Prof. F. Grosveld; co-promotor: Dr. K. Wendt. Aude Guénolé is op 25 juni gepromoveerd in Leiden op het proefschrift "Dissection of DNA damage responses using multiconditional genetic interaction maps". Promotor: Prof. L. Mullenders; co-promotor: Dr. H. van Attikum. Cathryn Poulton is op 26 juni in Rotterdam gepromoveerd op het proefschrift "Genes and mechanisms in primary microcephaly". Promotoren: Prof. R. Hofstra en Prof. F. Grosveld; co-promotor: Dr. G. Verheijen-Mancini. Ruud Jorna hoopt op 1 oktober te promoveren in Rotterdam op het proefschrift "Disturbance of transcription factor dynamics in mammalian cells: knock-


http://www.mgcworkshop.nl/


in, knock-down, knock-out or anchor-away". Promotor: Prof. F. Grosveld. Xiao Yu hoopt op 2 oktober in Rotterdam te promoveren op het proefschrift "Formation of transcription factor complexes during embryonic erythroid development". Promotor: Prof. F. Grosveld. Divine Kulu hoopt op 9 oktober in Rotterdam te promoveren op het proefschrift "The role of Sp1 and Sp3 in hematopoiesis". Promotor: Prof. S. Philipsen. Elmar Tobi hoopt op 29 oktober te promoveren in Leiden op het proefschrift "Epigenetic differences after prenatal adversity: The Dutch Hunger Winter". Promotor: Prof. P. Slagboom; co-promotoren: Dr. B. Heijmans en Dr. L. Lumeij. Maarten van Iterson hoopt op 28 november in Leiden te promoveren op het proefschrift "The power of high-dimensional data in genomics research". Promotor: Prof. GJ. van Ommen. Willemijn Passtoors hoopt op 19 december te promoveren in Leiden op het proefschrift "Transcriptomic studies in human ageing and longevity". Promotoren: Prof. P. Slagboom en Prof. G. van Ommen; co-promotor: Dr. M. Beekman. Nieuwe medewerkers Bij de afdeling Anatomie en Embryologie (Leiden): Susana Chuva de Susa Lopes wordt per 1 oktober aangesteld als onbezoldigd gastprofessor (Universiteit Gent) en is belast met een opdracht van 5% wetenschappelijk onderzoek in het vakgebied Development biology, Stem Cell biology and Epigenetics. Bij de afdeling Celbiologie (Rotterdam): Sreya Basu has started as a postdoc in Niels Galjart's group on April 1st. Her research concerns the function of microtubules and their associated proteins in the development and maintenance of the neuro-muscular junction. Three new PhD students started working: Sylvia Hoeboer, in Sjaak Philipsen's lab. She will identify adult-stage gamma-globin

suppressors genetically, using mouse models of human globin switching. The long-term objective is to develop reagents that interfere with the function of these suppressors, with the aim to reactivate gamma-globin expression in adult beta-thalassemia and sickle cell disease patients. In Niels Galjart's group Luca Signorile has started working on mechanisms of microtubule plus-end tracking. Finally, Marti Quevedo Calero has started with Raymond Poot. He works on the mechanism of gene regulation in embryonal stem cells. Bij de afdeling Genetica (Rotterdam): Yasemin Turkyilmaz has started as of April 1st as a PhD student in the group of Wim Vermeulen, under supervision of Jurgen Marteijn. She will be working on regulation of NER. As of May 1st, Mariangela Sabatella has starts as PhD student in the group of Wim Vermeulen, under supervision of Hannes Lans. She will be working on ERCC1/XPF proteins, as part of the FP7-ITN project 'aDDRess'. On October 1st, Eleonora Orlanda will start as a PhD student in the group of Jan Hoeijmakers, under supervision of Joris Pothof. She will be working on Epigenetics of DNA repair and its role in ageing, as part of the FP7-ITN project 'aDDRess'. Akos Gyenis will start on October 1st as a postdoc in the group of Jan Hoeijmakers, also working on Epigenetics of DNA repair and its role in ageing, as part of the FP7-ITN project 'aDDRess'. Bij de afdeling Humane Genetica (Leiden): Onderzoekers: Sylvia le Devedec (projectleiders: Peter-Bram ’t Hoen en Maaike Vreeswijk) gaat werken aan transcriptoom data analyse in het kader van borstkankeronderzoek. OIO's: Marlinde van den Boogaard (projectleider: Silvère van der Maarel) gaat haar promotieonderzoek wijden aan (epi)genetische modifiers in FSHD. Saeed Katiraei (projectleider: Ko Willems van Dijk) zal onderzoek gaan doen naar de rol van de darmflora bij het metabool


syndroom en hart- en vaatziekten. Dit project wordt gesubsidieerd door het Rembrandt Instituut. Overig: Rajaram Kaliyaperumal (projectleiders: Marco Roos) is wetenschappelijk program-meur en maakt deel uit van het Biosemantiek Ontwikkel team. Hij zal zich richten op de bevraging en publicatie van genomische datasets. Joke van der Meulen (projectleider: Annemieke Aartsma-Rus) is een nieuwe researchanalist in de DMD Genetische Therapie groep. Haar werk zal zich richten op het vaststellen van de therapeutische potentie van myostatine en TGF-β remmers in muismodellen van Duchenne Musculaire Dystrofie en het ophelderen van het moleculaire mechanisme van myostatin/TGF-β signaaltransductie in dystrofische spieren. Bij de afdeling Toxicogenetica (Leiden): Bharath Sampadi started in June as a PhD student on a EU-funded project RISK-IR under supervision of Harry Vrieling and Leon Mullenders. Bharath will be performing a systems analysis of the biological responses of mouse embryonic stem cells to low doses of ionizing radiation. Romy Mesman started in September as a PhD student on the KWF-funded project “Functional testing of variants of uncertain clinical significance in breast cancer genes to improve DNA diagnostics and cancer risk assessment” under supervision of Maaike Vreeswijk, Harry Vrieling and Christi van Asperen. Ana Martins-Pardillo has just started in the group of Niels de Wind. She will investigate the role of replicative stress at endogenous DNA damage in ageing and ageing-related cancer. To this aim she will use mice with a targeted disruption in the DNA translesion synthesis gene Rev1. Lezingen/symposia NKI Seminars are given at the NKI, Plesmanlaan 121, Amsterdam: Location: Piet Borst Auditorium, 11.00 hrs. September 27: Manolis Pasparakis "RIP kinases in cell death and inflammation".

October 4: Dean Fennell "Novel strategies for engaging Apoptotic Pathways in Mesothelioma". October 11: Michiel Vermeulen "Quantitative proteomics for epigenetics". October 18: Haico van Attikum "Dissecting the DNA damage response network". November 1: Simon Tavare "Statistical issues in studying tumour heterogeneity". November 8: Floor van Leeuwen "Late effects of radiotherapy and chemotherapy for Hodgkin lymphoma". November 15: Simon Boulton "Genome stability and the control of homologous recombination". November 29: Peter Fraser "Single molecule analyses of chromosome structure and genome organization using single cell Hi-C". December 6: Peter Savage "Development and specificity of tumor-associated regulatory T cells". December 13: Silvère van der Maarel "Epigenetic regulation of large tandem repeat arrays in the human genome: lessons from epigenetic disorders". Further info at www.nki.nl Sectie 'DNA herstel-mechanismen' De volgende bijeenkomst zal plaatsvinden op vrijdag 25 oktober in Leiden, LUMC, aanvang 9.30 uur. Deze sectie komt ca. 1 x per 2 maanden bijeen op een vrijdagochtend, alternerend in Leiden en Rotterdam. Coördinatoren: Leon Mullenders (: 071-5269600) en Wim Vermeulen (: 010-7043194). Sectie ‘Lysosomal Storage Diseases’ Eens per week overleggen betrokkenen van de afdelingen Kindergeneeskunde, Klinische Genetica, Neurologie, Interne Geneeskunde, Ziekenhuis Apotheek en andere afdelingen van het Erasmus MC over de lopende zaken wat betreft patiëntenzorg en onderzoek aangaande lysosomale stapelingsziekten. Hierbij staat de toepassing van enzymvervangingstherapie en daaraan gerelateerd onderzoek centraal (ziekte van Pompe, ziekte van Hurler, ziekte van Hunter en Maroteaux-Lamy). De bijeenkomsten worden gehouden in het

http://www.nki.nl/


Sophia kinderziekenhuis, Dr Molewaterplein 60, Rotterdam. Voor meer informatie kunt U terecht bij Pim Pijnappel: 010-7043357; [email protected]. Verkregen subsidies Wim Vermeulen (Genetica, EMC) ontvangt een Advanced Grant van 2,5 miljoen euro voor zijn onderzoek naar de reparatie van schade in ons DNA. Beschadigingen in het DNA leiden tot veroudering en zelfs kanker. Verschillende reparatiemechanismen beschermen ons hiertegen. “Deze reparatiemechanismen zijn een belangrijk doelwit voor kankerbehandelingen”, zegt Vermeulen. “Maar om een effectieve therapie te kunnen ontwikkelen, moeten we eerst weten hoe ze worden gereguleerd en hoe ze met elkaar samenwerken. Deze subsidie geeft ons de mogelijkheid hier uitgebreid onderzoek naar te doen.” http://www.erasmusmc.nl/1172194/2013/vruchtbare.zomer.voor.rdam.onderzoekers Personalia/Prijzen Brigit den Adel (Anatomie, LUMC) heeft voor de derde keer op rij de posterprijs gewonnen op de EMIM (European Molecular Imaging Meeting) 2013 in Turijn. Margot Bartelings heeft de Innovatieprijs van Boerhaave Nascholing ontvangen voor de cursus "Foetale echocardiografie". Harsha Devalla heeft de 2e prijs "Young Investigator Award" behaald tijdens de Duits Nederlandse bijeenkomst in Heidelberg. Frank Grosveld (Cell Biology, EMC) will retire on August 1st 2013. At that time he will step down as head of the department of Cell Biology. Appointed successor to Frank Grosveld is Danny Huylebroeck (from the University of Leuven, Belgium) who started per July 1st and will take over the responsabilities as departmental Head of Cell Biology per August 1st. After a short retirement Frank

Grosveld will rejoin the department per September 1st to succeed his scientific work as regular professor in Cell Biology. Frank Grosveld and Jan Hoeijmakers both received a royal honor on the 27th of April for their contributions to science; they have been elevated to 'Ridder in de Orde van de Nederlandse Leeuw". Frank Grosveld in Rotterdam; Jan Hoeijmakers in Zevenhuizen.

Beerend Hierck (Anatomie, LUMC) heeft in juni de Tamminga prijs voor beste docent 2012-2013 ontvangen. Roland Kanaar (Genetica, EMC), expert in DNA-reparatie, is door de wetenschapsorganisatie KNAW als nieuw lid uitgekozen. Eerbetoon De uit 1808 stammende KNAW is een genootschap van excellente Nederlandse wetenschappers, zo vermeldt de website. Leden worden gekozen op basis van hun wetenschappelijke prestaties. Een lidmaatschap is voor het leven en geldt als ‘een groot eerbetoon’. Herstel Roland Kanaar (1961) levert met zijn onderzoek een belangrijke bijdrage aan het begrip van de genetische stabiliteit in relatie tot kanker en aangeboren aandoeningen, schrijft de KNAW. Kanaar bekijkt het proces van schade en herstel van het DNA op alle niveaus. Verwarming De KNAW over Kanaar's werk: “Cellen kunnen veel schade repareren, maar ze doen dat helaas ook met schade die door bijvoorbeeld bestraling ontstaat aan tumoren. Kanaar toonde onlangs aan dat


http://www.erasmusmc.nl/1172194/2013/vruchtbare.zomer.voor.rdam.onderzoekers

http://www.erasmusmc.nl/1172194/2013/vruchtbare.zomer.voor.rdam.onderzoekers


door verwarming tot 42 graden een van de reparatiesystemen in het DNA wordt uitgeschakeld. In combinatie met medicijnen kan dit voor bepaalde kankerpatiënten een nieuwe behandeling vormen.” Egbert Lakke (Anatomie, LUMC) was genomineerd voor de LUMC prijs voor beste onderwijscursus "Introductions in to neurosciences". Julie Rutten (Humane Genetica, LUMC) heeft tijdens de Genetica Retraite 2013 te Rolduc de 2e prijs uitgereikt gekregen voor haar voordacht 'Cysteine quantity correction in CADASIL; modification of the

NOTCH3 protein using anti-sense oligonucleotides’. Ze won hiermee een iPod Touch.

MGC-Bulletin no. 50 Het vijftigste MGC Bulletin is gepland voor maart 2014. De sluitingsdatum voor kopij is gesteld op 15 februari 2014. Mededelingen, nieuws, agendapunten en andere wetenswaardigheden gaarne per e-mail inleveren bij Madeleine Nivard of Ingrid Braxhoven, afdeling Toxicogenetica, [email protected]/ [email protected].


23rd MGC-SYMPOSIUM Thursday, September 19, 2013

"Engels", Stationsplein 45, Rotterdam Program 23rd MGC Symposium 8.45 coffee and registration 9.30 opening: F.G. Grosveld Chairman: F.G. Grosveld 9.35 JiangLing Xiong: “Integrin signaling through TGFβ/miR200/ZEB network regulates epithelial

gene expression and controls breast cancer metastatis"(LACDR-Toxicology, UL) 9.55 Haleh Rafati: “Induction of the Wnt signaling pathway by natural ligands or small molecule

inhibitors activated latent HIV (Biochemistry, Erasmus MC) 10.15 Sara Martins-Neves: "Wnt/β-catenin signaling in osteosarcoma cancer stem cells" (Pathology,

LUMC) 10.35 Best lecture of the MGC PhD Workshop 2013

Agnese Loda: "Autosomal spreading of Xist revisited" (Reproduction and Development, Erasmus MC)

10.55 coffee/tea

Chairman: L.H.F. Mullenders 11.15 Bert-Jaap van Belle: "DNA-damage sensor XPC differentiates between low and high damage

load" (Optical Image Centre, Erasmus MC) 11.35 Joost Schimmel: “Purification, identification and characterization of novel SUMO target

proteins” (Molecular Cell Biology, LUMC) 11.55 Gerline van der Glind: “Quiescent stem cells in skin accumulate cyclobutane pyrimidine dimers

under low level UV exposure, giving rise to carcinomas upon TPA tumor promotion” (Dermatology, LUMC)

12.15 Wilbert Vermeij: “Effect of DR on life span and neurodegeneration in progeroid DNA repair deficient mouse models” (Genetics, Erasmus MC)

12.35 -14.00 lunch

Chairman: R.M.W. Hofstra 14.00 Aniek van der Vaart: “Studying intraflagellar transport in cilia of Caenorhabditis elegans by

dual-color live imaging" (Cell Biology, Erasmus MC) 14.20 Andrea Martella: “Genome-wide analysis of Ldb1 binding in hemangioblasts reveals novel

signaling pathways involved in primitive hematopoiesis” (Cell Biology, Erasmus MC) 14.40 Yunia Sribudiani: “Genetic and functional studies in Hirschsprung disease” (Clinical Genetics,

Erasmus MC)

Chairman: J.H.J. Hoeijmakers 15.00 Cathelijne van den Berg: “Pluripotent stem cell models of a human cardiac sodium

channelopathy” (Anatomy and Embryology, LUMC) 15.20 Muhammad Riaz: “Masking the proximal polyadenylation site of the E3-ligase ARIH2 restores

PABPN1 levels in aging-associated muscle degeneration” (Human Genetics, LUMC) 15.40 Mark Drost: “Novel methods for the diagnosis of missense variants in DNA mismatch repair

genes in Lynch syndrome" (Toxicogenetics, LUMC)

16.00 coffee/tea

Chairman: G.J.B. van Ommen 16.30 MGC Symposium Lecture: Prof. dr. Christopher Pearson: "Repeat-associated diseases,

pathogenesis & therapeutic avenues" (The Hospital for Sick Children, Department of Genetics, Toronto, Canada)

17.30 drinks

18.30 dinner


Abstracts 23rd MGC Symposium

Integrin signaling through TGFβ/miR200/ZEB network regulates epithelial gene expression and controls breast cancer metastatis JiangLing Xiong LACDR-Toxicology, UL Integrin-mediated extracellular matrix (ECM) adhesion provides normal and cancer cells with survival and proliferation signals. Integrin-blocking antibodies and small molecules are in trials for anticancer therapy. Here, we show that disruption of integrin-mediated extracellular matrix (ECM) adhesion causes extensive gene expression reprogramming in mouse and human breast cancer cells. This includes alterations in the TGFβ-BMP signaling network that shift the balance between miR-200 microRNAs and ZEB transcriptional repressors; causing a block in E-cadherin transcription. As a consequence, while integrin depletion attenuates tumor growth as predicted, it also triggers a switch from collective invasion to individual cell migration that augments tumor cell dissemination. Collective invasion can be reestablished by restoring the network at the level of TGFβR, ZEB, miR-200, or E-cadherin expression, which arrests dissemination without affecting tumor growth. These findings reveal that integrin-mediated ECM-attachments support a signaling network in control of epithelial gene expression that suppresses metastasis. The data indicate that caution is warranted in the use of integrin antagonists for anticancer therapy. Induction of the Wnt signaling pathway by natural ligands or small molecule inhibitors activated latent HIV Haleh Rafati Biochemistry, Erasmus MC

• Background: Highly Active Antiretroviral therapy (HAART) is very effective in suppressing replication of HIV. However, during HAART, HIV persists lifelong as a latent virus in the patient’s memory CD4+T cells. This latent HIV reservoir is transcriptionally competent and cessation of HAART leads to renewed active viral replication. Therefore, in order to eradicate HIV from infected patients, this latent viral reservoir has to be targeted and activated for subsequent elimination by HAART. • Methods: Using J-Lat and S-Lat CD4+ T cell line models as

well as ex vivo infected primary CD4+ T cell models reflecting HIV latency we examined the role of the Wnt signaling pathway in regulation of transcription of the latent HIV LTR. We also used various biochemical assays probing the nucleosomal landscape of the latent and Wnt-activated HIV LTR to delineate the mechanism by which Wnt signaling regulates HIV. • Results: We find that activation of the Wnt pathway by natural ligands or small molecule inhibitors resulted in activation of the latent HIV LTR. Treatment of latently HIV infected cells with activators of the Wnt pathway resulted in recruitment of TCF/LEF and b-catenin, the molecular effectors of Wnt signaling, to the latent HIV LTR. Wnt-mediated activation of the latent HIV LTR was synergistically enhanced in the presence of histone deacetylase inhibitors, a class of drugs currently under clinical investigation for activation of latent HIV. • Conclusions: Targeting the Wnt pathway by small molecules and Wnt agonists may be an attractive strategy in a combinatorial therapy aimed at activation of latent HIV infected cells followed by their elimination in the presence of HAART.


Wnt/ β-catenin signaling in osteosarcoma cancer stem cells Sara Martins-Neves Pathology, LUMC Osteosarcoma is a malignant bone tumour afflicting mainly young patients. Although survival has improved substantially since the introduction of multimodal chemotherapy, still 40% of the patients die because of therapy resistant metastasizing tumour cells. Recent studies pointed out for human mesenchymal stem cells as the cell-of-origin of osteosarcoma, and the disease is envisaged as resulting from defective stem cell differentiation[1]. Hence, osteosarcoma appears to be an adequate candidate to fit into the cancer stem cell (CSCs) model, but little is known about the specific mechanisms governing osteosarcoma CSCs’ self-renewal. We therefore aimed to explore the role of Wnt/β-catenin signalling pathway in osteosarcoma CSCs and if its inactivation could sensitise CSCs towards conventional chemotherapy. Using a well-established sphere assay model[2], we isolated putative CSCs from osteosarcoma cell lines. CSCs expressed pluripotency-related genes (SOX2, KLF4), were capable to differentiate into multiple mesenchymal lineages and had increased activity of the stem-cell marker Aldefluor®, in comparison with respective parental cells. Importantly, spheres, but not parental cells, contained a fraction of cells with nuclear β-catenin-positivity, which is a hallmark of activated Wnt/β-catenin signalling, as determined by immunohistochemistry. Gene expression in CSC enriched spheres revealed increased constitutive mRNA levels of AXIN2, a specific target gene of activated Wnt/β-catenin signalling, and decreased levels of the secreted Wnt antagonist DKK1 as compared to parental cells. We have previously shown that Wnt/β-catenin signalling in conventional high-grade osteosarcoma is not active[3]. CSCs were highly resistant to doxorubicin, cisplatin and methotrexate, the first-line chemotherapy applied to osteosarcoma patients, having IC50 values ≥2-fold higher than their parental cells. Pharmacological inactivation of Wnt signalling using IWR-1 (a tankyrase inhibitor) elicited a significant cytotoxic effect on CSCs from spheres, reducing their viability after 48h of drug exposure. Combination of IWR-1 with low doses of doxorubicin, cisplatin or methotrexate diminished cell viability during the same time-period, probably due to the elimination of non-CSCs present in the spheres. This effect was significantly less pronounced in parental cells, which have inactive Wnt signalling, in accordance with absent nuclear expression of β-catenin. Conversely, pharmacological stimulation of Wnt signalling in parental cells using SB216763 (a GSK-3β inhibitor) antagonised the sensitivity of cells towards doxorubicin, cisplatin and methotrexate, after 48h of drug incubation, as determined using similar drug combination experiments. In conclusion, Wnt/β-catenin appears to be specifically activated in the sub-population of possible CSCs in osteosarcoma. Our results suggest that selectively targeting the Wnt/β-catenin pathway can eliminate CSCs, while current chemotherapeutic agents can only eradicate bulk tumour mass. Combining conventional chemotherapy with Wnt inhibition in the treatment of osteosarcoma can simultaneously contribute to reduce the doses of chemotherapy and eradicate the CSC sub-population, which is thought to be involved not only in cancer progression, but also in recurrence. [1] Tang et al. Clin Orthop Relat Res. 2008 Sep;466(9):2114-30. [2] Martins-Neves et al. BMC Cancer. 2012 Apr 4;12:139. [3] Cai et al. J Pathol. 2010 Jan;220(1):24-33.


Autosomal spreading of Xist revisited Agnese Loda Reproduction and Development, Erasmus MC

In mammals, dosage compensation of sex chromosomal genes between females (XX) and males (XY) is achieved through X chromosome inactivation (XCI). This epigenetic phenomenon involves non-coding RNAs, antisense transcription and histone modifications to distinguish two genetically identical X chromosomes as active (Xa) and silent (Xi) entities within the same nucleus. At the onset of XCI, the X-linked non-coding Xist gene is transcriptionally up-regulated on the future Xi. Xist RNA coats the Xi in cis triggering chromosome wide transcriptional inactivation. Although Xist is the major player of the process the

molecular mechanism by which Xist RNA spreads along the entire length of the X chromosome is an intriguing open question. Notably, many X to autosome translocations show either inefficient Xist spreading or incomplete inactivation of the autosomal translocated material, suggesting a sequence specific model for Xist spreading in cis (White et al. 1998, Popova et al. 2006). In this context, LINE repetitive elements, which are enriched on X chromosome relative to autosomes have been implicated to confer X-chromosome specificity (Lyon et al. 1998). Nevertheless, we hypothesize that the lack of autosomal inactivation observed in cells with X:autosome translocations reflects negative selection against those cells in which Xist spreading was efficient enough to transcriptionally inactivate the autosomal fraction of the translocation product thus leading to lethal aneuploidy. To further investigate this hypothesis we generated (41, XX dup12) ES cell lines with a tetracycline-responsive Xist transgene integrated on chromosome X, 12, or other autosomes. The use of polymorphic ES cell lines allows us to evaluate the degree of gene inactivation by performing allele specific expression analysis. Silencing of one of the three chromosome 12’s in these (41, XX dup12) ES cell lines will not be lethal similar to silencing of one X chromosome in female cells. This may contrast with ES cell lines harbouring transgene integrations on other autosomes. Therefore, comparison of Xist mediated silencing in these different ES cell lines will indicate whether aneuploidy or the LINE density explains reduced Xist spreading on autosomes. DNA-damage sensor XPC differentiates between low and high damage load Bert-Jaap van Belle Optical Imaging Centre, Erasmus MC Nucleotide excision repair (NER) removes helix-distorting DNA-damages like those inflicted by the UV component of sunlight. These lesions are detected by the damage sensing complexes XPC and UV-DDB. After damage recognition, the damage is removed in a coordinated, well described set of reactions, including damage verification and unwinding, excision of the damaged strand, and DNA synthesis and ligation. In several DNA repair pathways adaptive response mechanisms have been described, in which exposure to challenging conditions sensitizes the repair machinery to prepare the cell for worse to come. Adaptive responses that have been described so far are induced by low dose exposure. However, it is not known whether adaptive or differential response mechanisms exist, that are induced by high dose exposure. Using GFP-tagging and photobleaching combined with RNA silencing, we show that the damage sensing XPC-complex operates as a molecular switch: above a threshold level of UV-irradiation, a fraction of XPC-complexes switches to a different DNA-binding mode resulting in permanent immobilisation, instead of transient DNA-interactions observed


during repair after low dose exposure. Interestingly, this fraction does not increase with further increasing UV-dose, suggesting a bistable equilibrium between the two binding modes. The switch is at least controlled by XPC-ubiquitylation as down regulation of the E3-ligase Cullin 4a leads to stable XPC-binding in a dose dependent manner, also at low damage concentrations. We hypothesise that the observed switching enables the cell to differentiate between low stress level, requiring moderate response, and high stress level, which calls for different action. Purification, identification and characterization of novel SUMO target proteins Joost Schimmel Molecular Cell Biology, LUMC

The functional diversity of the proteome is expanded by covalent post-translational modifications (PTMs) of amino acids in proteins. One of these PTMs, the covalent attachment of Small Ubiquitin like Modifiers (SUMO) to proteins, has proven to regulate a wide variety of cellular processes. Research in our group focuses on identifying target proteins for SUMOylation by using mass-spectrometry based approaches and on elucidating the functional consequences of SUMOylation on specific target proteins.

I am focusing on the role of SUMOylation in cell cycle progression. Loss of SUMO modification results in severe defects in nuclear organization including missegregation of chromosomes, leading to genomic instability. To get more insight into the relevant SUMO targets responsible for these defects, we performed a proteome-wide study on SUMOylation dynamics during cell cycle progression. One of the key SUMO target proteins identified in our screen is the transcription factor FoxM1. FoxM1 plays a key role in cell cycle progression by activating the expression of a set of genes that are essential for proper mitosis. We observed that FoxM1 SUMOylation increases in these phases of the cell cycle where full FoxM1 activity is required. Furthermore we found that SUMOylation enhances FoxM1 transcriptional activity by inhibiting the interaction between the repressor domain and activation domain of the protein. Together, these findings show that SUMO affects cell cycle progression by altering the SUMOylation levels of a large set of proteins. Quiescent stem cells in skin accumulate cyclobutane pyrimidine dimers under low level UV exposure, giving rise to carcinomas upon TPA tumor promotion Gerline van der Glind Dermatology, LUMC At daily low level UV exposure – not causing any hyperplasia – cyclobutane pyrimidine dimers (CPDs) can accumulate in genomic DNA of quiescent stem cells in the skin (in contrast to faster repaired 6-4 photoproducts which do not accumulate). When these CPD-retaining cells are forced to proliferate mutations may occur. The aim of this study was to investigate if such a forced proliferation gives rise to p53-mutant overexpressing clones and ultimately to skin carcinomas. CPD-retaining cells were induced in SKH mice by 40 days of low-level daily UV exposure at 1/7th of the threshold dose for a sunburn. These cells were observed in the epidermis mostly in the basal layer (1.3% of basal cells). A control group that received the same total UV dose (5.6 times threshold sunburn dose) in a single high exposure on day 1 did not show any CPD-retaining cells after 40 days. As of 47 days after


the start of the experiment both groups received TPA treatment for 20 weeks to induce cell proliferation. After the first TPA application CPDs were observed in the suprabasal layers in the fractionated exposure group, and after 8 weeks of TPA treatment mutant p53-overexpressing foci were observed only in this group (about 1 focus per 5000 CPD-retaining basal cells). Survival free of “non-papilloma” tumors (suspected carcinomas and precursing actinic keratoses) was significantly shorter in this group, but for frank papillomas there was no significant difference between the two groups. Non-papilloma tumours went into regression after discontinuation of TPA in the unfractionated UV exposure group, but persisted and increased in the fractionated exposure group (0.06 vs 2.25 tumours >4mm/mouse at day 280). Our data indicate that quiescent stem cells are targeted by low level chronic UV exposure to give rise to skin carcinomas. Effect of DR on life span and neurodegeneration in progeroid DNA repair deficient mouse models Wilbert Vermeij Genetics, Erasmus MC

E rcc1∆/- mice are short living DNA repair deficient mutants presenting a wide range of accelerated aging features, including loss of synaptic plasticity, reduced motor and cognitive functions, and neuronal degeneration (Borgesius et al., 2011, J Neurosci 31: 12543). To further validate Ercc1∆/- mice as a mouse model for testing anti-aging and neuroprotective interventions, we studied the effect of dietary restriction, which is well-known to extend lifespan and reduce age-related pathology in many species, including primates. Dietary

restriction (DR) of 30% resulted in a more than 2 fold increase in life span with a median lifespan of 43.8 weeks and 21.1 weeks in DR versus ad libitum (AL) fed Ercc1∆/- mice, respectively. The large effect on survival was paralleled by delayed onset and reduced severity of motor abnormalities in DR Ercc1∆/- mice. Neuropathological comparison of AL and DR Ercc1∆/- mice at 16 week of age, revealed decreased astrocytosis and microgliosis and reduced numbers of p53-positive cells in brain and spinal cord of DR Ercc1∆/- mice. Quantitative stereological analysis showed substantial higher levels of NeuN-positive cells in cortex of DR versus AL Ercc1∆/- mice. Together the data indicate a strong neuroprotective effect of dietary restriction in Ercc1∆/- mice. The data support the idea that cumulative DNA damage contribute to the age-related functional and structural deterioration of the nervous system, and that the beneficial effect of dietary restriction in part operates by reducing the amount of DNA damage. Studying intraflagellar transport in cilia of Caenorhabditis elegans by dual-color live imaging Aniek van der Vaart Cell Biology, Erasmus MC Cilia are cellular extensions present on nearly all vertebrate cells. They can be classified into two groups; primary and motile cilia. Primary cilia function in sensing physical and biochemical signals from the environment, while motile cilia, or flagella, function in cell locomotion and the generation of fluid movement. Cilia formation, maintenance and function depend on a specialized transport system called intraflagellar transport (IFT). During IFT, particles are transported from the ciliary base to its tip (anterograde) and back (retrograde). IFT is important for structural and functional plasticity of cilia and plays an important role in the regulation of cilium length and in the localization of proteins in cilia.


We study IFT and its effects on the regulation of cilium length in the amphid channel cilia of C. elegans. These cilia are divided in a middle and a distal segment. In the middle segment, anterograde IFT is mediated by two kinesins, kinesin-II and OSM-3 (mammalian KIF17), while only OSM-3 enters the distal segment. In addition to the motors and the cargo, which include ciliary building blocks as well as signaling molecules, IFT particles contain at least three other protein complexes, including the BBSome, which consist of proteins involved in the human cilia-related disease Bardet Biedl Syndrome. The functions of these proteins are not completely understood, but they are thought to have a role in particle stabilization.

In a previous study, we have shown that mutation of a heterotrimeric G protein α-subunit, gpa-3, affects cilium length and IFT: animals that carry a dominant active mutation in gpa-3 (gpa-3QL) have shorter cilia, and the coordination of IFT by the two kinesins is affected. In animals that have lost gpa-3 cilia are slightly longer and IFT is affected. Our results suggest that GPA-3 transduces a signal detected from the environment that modulates cilium length and/or the localization of proteins in cilia by the IFT machinery.

To find out how G protein signaling modulates IFT, we performed a forward genetic screen for suppressors of the short cilia phenotype of gpa-3QL animals. We identified several mutants in which cilium length has been restored to wild type. Genes mutated in these suppressor mutants include the Golgi protein SQL-1/GMAP210, the E2 ubiquitin conjugating enzyme variant UEV-3 and the p38 MAPK PMK-3. We are currently studying the functions of these proteins in regulating IFT and cilium length. To study the effects of the above described genes on IFT, we use dual-color live imaging of fluorescently tagged IFT proteins to determine their localization and speed in cilia. With these data we can infer the composition of IFT particles in both wild type and mutant C. elegans. Our preliminary results indeed confirm that in wild type animals particles are transported by both kinesins together. We are currently testing what happens in various mutant animals e.g. in gpa-3 and bbs mutants. Genome-wide analysis of Ldb1 binding in hemangioblasts reveals novel signalling pathways involved in primitive hematopoiesis Andrea Martella Cell Biology, Erasmus MC

The first site exhibiting hematopoietic activity in mammalian development is the yolk-sac blood island, which originates from the hemangioblast. The hemangioblast development and the establishment of the primitive erythroid lineage in the yolk sac is a process regulated by the complex interplay that exists between transcription factors and signaling pathways. In this study we performed genome-wide molecular and functional studies in blast colony-forming cells to gain insight into the function of the essential Ldb1 factor in early primitive hematopoietic development. Transcriptome analysis and correlation with the genomewide binding

pattern of Ldb1 in hemangioblasts revealed a number of direct-target genes and pathways misregulated in the absence of Ldb1. Among these signaling pathways, MAPK-ERK and IGF1R pathways emerged as new candidates for the regulation of hemangioblast development. We therefore used the embryonic stem cell differentiation system to define the role of MAPK-ERK and IGF1R pathways at two distinct stages of primitive hematopoiesis: formation of Flk1+ mesoderm and induction of hematopoietic progenitors. We show that, at the mesodermal stage, activation of both pathways regulates the antagonistic commitment between hematopoiesis and cardiogenesis supporting the emergence of hemangioblasts at the expense of cardiovascular progenitors. Only MAPK-ERK pathway is involved in the following stage of hemangioblast differentiation and its activation regulates the balanced


generation of endothelial and primitive hematopoietic cells contrasting the hematopoietic commitment. Together, these findings demonstrate that the specification of the primitive erythroid lineage is controlled, in part, by the action of MAPK-ERK and IGF1R pathways. Finally, by revealing novel genes and pathways not previously associated with early development, our study provides novel candidate targets to manipulate the differentiation of hematopoietic and/or endothelial cells. Genetic and functional studies in Hirschsprung disease Yunia Sribudiani Clinical Genetics, Erasmus MC

Hirschsprung disease (HSCR) is a congenital disease characterized by the absence of ganglia in the myenteric and submucosal plexus of the gastrointestinal (GI) tract. RET is a major genetic risk factor for HSCR, as RET coding sequence mutations have been identified in ~50% of the familial cases and in 15-35% of the sporadic cases. Besides rare coding RET mutations also very common, and highly associated RET haplotype was found (homozygous in ~62-85% in HSCR patients versus homozygous in 20-40% in the normal population, resulting in an of OR > 20.

In this talk we will show functional data proving which SNP on the disease associated haplotype is contributing to disease development and also we will show how this SNP eventually contributes to disease development. Moreover, we screened for novel HSCR candidate genes by performing exome sequencing in sporadic and familial HSCR cases and we functionally studied some of the rare variants we identified.

Association results in combination with in silico predictions pointed towards the involvement of SNP rs2506004 in HSCR. We found that the wild type allele is in a binding site for NXF/ARNT2 and SIM2/ARNT2, which are transcription activators and repressors, respectively. The mutant allele changes the binding capacity for these transcription factors and we could show that the disease associated variant has an effect on the expression of RET.

Using an exome sequencing strategy, we identified rare inherited variants in RET, IHH and LRBA in a family with five affected members and 16 de novo mutations were identified in 20 sporadic HSCR cases. Functional studies showed that variants in the RET and IHH coding sequence, are pathogenic. Functional studies for the de novo variants is ongoing.

These studies points towards a crucial role for RET mutations and variations in HSCR development, however, besides RET many other genes contribute to disease development. Pluripotent stem cell models of a human cardiac sodium channelopathy Cathelijne van den Berg Anatomy and Embryology, LUMC

Mutations in the gene encoding the cardiac sodium channel, SCN5A, have been implicated in multiple cardiac arrhythmia syndromes, such as long-QT syndrome type 3 (LQT3) and Brugada syndrome. While most mutations lead to one particular electrophysiological disorder, several single SCN5A mutations present multiple clinical manifestations (the so-called overlap syndromes). Several transgenic mouse models carrying the mouse equivalent of human SCN5A mutations have been generated, which recapitulate the disease phenotype observed in humans. Pluripotent stem cells (PSCs) offer a new paradigm for modeling genetic cardiac diseases. However, it is unclear whether mouse and human PSCs can

truly model both gain and loss of function genetic disorders affecting the Na+ current due to


the immaturity of the PSC-derived cardiomyocytes. To address this issue, we generated multiple PSC lines containing a Na+ channel mutation causing a cardiac Na+ channel overlap syndrome. Induced PSC (iPSC) lines were generated from mice carrying the Scn5a1798insD/+ (Scn5a-het) mutation. These mouse (m)iPSCs, along with wild-type miPSCs, were compared to the targeted mouse embryonic stem cell (mESC) line used to generate the mutant mice and to the wild-type mESC line. miPSCs resembled mESCs in morphology and expressed endogenous pluripotency markers. Following differentiation into cardiomyocytes, the electrophysiological properties of these cells were examined and found to recapitulate the phenotype observed in primary cardiomyocytes isolated directly from adult Scn5a-het mice. Finally, iPSCs were generated from a patient with the equivalent SCN5A mutation to ascertain whether some of the electrophysiological features underlying LQT3 and Brugada syndrome could also be detected in human cardiomyocytes. Patch-clamp measurements on the derivative cardiomyocytes revealed similar changes to those in the mPSC-derived cardiomyocytes. Collectively, these results demonstrate the utility of both ESC- and iPSC in modeling even complex ion channel disorders and indicate that the electrophysiological immaturity does not preclude their use as an accurate model for cardiac Na+ channel disease. Masking the proximal polyadenylation site of the E3-ligase ARIH2 restores PABPN1 levels in aging-associated muscle degeneration Muhammad Riaz Human Genetics, LUMC mRNA stability is regulated by Poly(A) Binding Protein 1 (PABPN1). Reduced levels of PABPN1 cause a genome-wide shift from distal to proximal polyadenylation site (PAS) usage. A decline in PABPN1 levels is aging-associated and lesser expression levels are found in skeletal muscles from oculopharyngeal muscular dystrophy (OPMD) patients. OPMD is a late-onset myopathy, caused by alanine-expansion mutation in PABPN1. In models for OPMD the alanine-expanded PABPN1 forms insoluble nuclear aggregates and as a consequence the levels of soluble PABPN1 decrease with a subsequent change in PAS usage. PABPN1 protein accumulation is regulated by the proteasome-ubiquitin system. We identified the E3-ligase, ARIH2, as a regulator of PABPN1 protein accumulation and aggregation. In turn, levels of ARIH2 mRNA are regulated by PABPN1 via proximal PAS usage. In muscle cell cultures masking the proximal PAS of ARIH2 by antisense oligonucleotides (AON) elevates the expression of both ARIH2 and PABPN1, and restores myogenic defects that are induced by reduced levels of ARIH2 or PABPN1. We suggest that the expression of both genes is maintained by a feed-forward regulatory loop between mRNA stability regulated by PABPN1, and PABPN1 protein turnover is regulated by ARIH2. Options to generate a mouse model for this feed-forward regulatory loop as well as the novel therapeutic AON-based approach to mask PAS of targeted genes and hence restoring mRNA expression levels will be used to maintain muscle functionality.


Novel methods for the diagnosis of missense variants in DNA mismatch repair genes in Lynch syndrome Mark Drost Toxicogenetics, LUMC

Lynch syndrome is a common inherited cancer susceptibility characterized by a high risk for the development of colorectal and other cancers. Lynch syndrome is caused by mutations in genes involved in the DNA mismatch repair pathway. Identification of the disease-causing mutation within families is important, as this confirms diagnosis and enables to discriminate between family members who are or are not at risk. This allows personalized preventive and curative healthcare for carriers of a pathogenic mutation. About 40% of all DNA mismatch repair gene mutations found in suspected Lynch syndrome patients are so-called Variants of Uncertain Significance (VUS), generally missense

mutations. This class of mutations poses a problem since it is difficult to distinguish between pathogenic, disease-causing, mutations and benign polymorphisms. We have developed in vitro and in vivo methods to diagnose Lynch Syndrome-related VUS. These methods are based on the profound knowledge of the genetics and the biochemistry of DNA mismatch repair. I will focus on the development and validation of these assays, and our efforts to integrate these methods in current Lynch syndrome diagnostics. This work provides a paradigm in bridging the gap between personalized genomics and personalized healthcare.

MGC Symposium Lecture Repeat-associated diseases, pathogenesis & therapeutic avenues Prof. dr. Christopher Pearson The Hospital for Sick Children, Department of Genetics, Toronto, Canada At least 40 neurodegenerative and neuromuscular diseases are caused by DNA mutations in gene-specific repeated DNA sequences, where the repeat tracts expand to increased numbers of repeat units. These repeat-associated diseases include Huntington’s disease, myotonic dystrophy, and Lou Gehrig’s disease. Most of these diseases are progressive as the individual ages. In the non-affected population these gene-specific repeats are genetically stable, while in affected families they expand upon parent-to-offspring transmission. Furthermore, the repeats continue to undergo expansion mutations as the individual ages, where the largest expansions occur in the more severely affected tissues like the brain, heart and skeletal muscle. Such ongoing repeat expansions are sources of increasing disease severity – making it particularly important to understand how these somatic mutations arise. Repeat mutations likely involve slipped-strand DNAs, formed by out-of-register mis-pairing of repeat units on complementary DNA strands. The formation and aberrant processing of these slipped DNAs is a likely source of mutations. I will present data that supports a role of how slipped-DNA structure and DNA mismatch repair are contributing to disease-associated repeat instability.


De MGC bestuurders en hun instituten Instituut Celbiologie 010-7043593 Erasmus MC Postbus 2040, 3000 CA Rotterdam hoofd: Prof.dr. F.G. Grosveld

(voorzitter MGC bestuur)

Centrum voor Humane en Klinische Genetica, LUMC 071-5269400 Postbus 9600, 2300 RC Leiden hoofd: Prof.dr. S.M. van der Maarel

(lid MGC bestuur) Prof.dr. G.J.B. van Ommen

(secretaris MGC bestuur)

Instituut Genetica 010-7043199 Erasmus MC Postbus 2040, 3000 CA Rotterdam hoofd: Prof.dr. J.H.J. Hoeijmakers

(lid MGC bestuur)

Afd. Toxicogenetica 071-5269600 Leids Universitair Medisch Centrum Postbus 9600, 2300 RC Leiden hoofd: Prof.dr. L.H.F. Mullenders

(lid MGC bestuur)

LACDR/ Toxicology 071-5276223 Faculteit W&N, Universiteit Leiden Postbus 9502, 2300 RA Leiden hoofd: Prof.dr. B. van de Water

(lid MGC bestuur)

Instituut Klinische Genetica 010-7043198 Erasmus MC Postbus 2040, 3000 CA Rotterdam hoofd: Prof.dr. R.M.W. Hofstra

(lid MGC bestuur)

Andere instituten/groepen binnen het MGC

Moleculaire Celbiologie, LUMC: (Prof.dr. H.J. Tanke & Prof.dr. A.K. Raap, Prof.dr. J. Noordermeer & Dr. L. Fradkin, Prof.dr. R. Hoeben, Prof.dr. J.A. Maassen en Prof.dr. P. ten Dijke)

Neurologie, groep neurogenetica, LUMC (Prof.dr. R.A.C. Roos, Prof.dr. J.J.G.M. Verschuuren en Prof.dr. M.D. Ferrari)

Huid- en geslachtsziekten, groep erfelijke melanomen, LUMC (Prof.dr. R. Willemze, Prof.dr. W. Bergman, Dr. F. de Gruijl en Dr. N.A. Gruis)

Pathologie: moleculaire tumorpathologie, LUMC (Prof.dr. P.C.W. Hogendoorn, Prof.dr. J. Morreau, Prof. J.V.M.G. Bovee en Prof.dr. P. Devilee)

Medische Statistiek: Moleculaire epidemiologie, LUMC (Prof.dr. T. Stijnen en Prof.dr. P.E. Slagboom) Anatomie en Embryologie, LUMC (Prof.dr. C.L. Mummery)

Instituut Pathologie, groep Fodde, Erasmus MC (Prof.dr. R. Fodde)

Optical Imaging Centre (OIC), Department of Pathology, Erasmus MC (Prof. Dr. A. B. Houtsmuller) Kinderheelkunde, Ontwikkelingsbiologie groep, Erasmus MC (Prof.dr. D. Tibboel)

Genetische epidemiologie, Erasmus MC (Prof.dr. C.M. van Duijn) Afd. Voortplanting en Ontwikkeling, Erasmus MC (Prof.dr. J.A. Grootegoed)

Forensische Moleculaire Biologie, Erasmus MC (Prof.dr. M. Kayser) Bioinformatica, Erasmus MC (Prof.dr. P. van der Spek)

Biochemie, Erasmus MC (Prof.dr. P. Verrijzer)

[n.b. verbeteringen voor deze lijst gaarne doorgeven aan het secretariaat]

Het MGC secretariaat is gevestigd op de afdeling Toxicogenetica, Leiden. 071-5269600; Fax 071-5268284 Directie secretaris: Dr. M.J.M. Nivard 071-5269605 e-mail: [email protected]


MGC-Bulletin, Nr. 49, September 2013 In dit nummer

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