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Professor Vincent Dion

Professor Vincent Dion

Professor, Dementia Research Institute

School of Medicine

+44(0)29 2251 0893
1.03 - Office J, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ
Available for postgraduate supervision


We are interested in gene editing and epigenome editing for expanded CAG/CTG repeats. These unusual sequences cause 13 different neurological disorders, including Huntington's disease and myotonic dystrophy. They all remain without effective treatments. We are looking for novel and innovative therapeutic avenues.


Vincent Dion started his scientific career in 1999 as a summer student in Stanley L. Miller’s laboratory at UCSD (USA). He also spent time as an undergraduate in the laboratories of Benoit Chabot and Reymund Wellinger at the University of Sherbrooke (Canada). He completed his B.Sc. in molecular biology and genetics in 2002 at the University of Guelph (Canada) with a honours thesis supervised by David H. Evans. In 2007, he obtained his PhD from Baylor College of Medicine (USA), under the supervision of John H. Wilson, for defining the role of DNMT1, the maintenance DNA methyltransferase, in preventing disease-causing CAG/CTG repeat expansions. As a postdoc with Susan M. Gasser at the Friedrich Miescher Institute (Switzerland), he discovered a novel role for chromatin remodeling enzymes in the repair of deleterious DNA double-strand breaks. He joined the Center for Integrative Genomics at the University of Lausanne (Switzerland) in 2013 on a professorship from the Swiss National Science Foundation. He became Professor at the UK Dementia Research Institut at Cardiff University in January of 2019. His lab has made key contributions towards the development of gene editing approaches to correct mutations that cause 14 different neurological, neuromuscular, and neurodegenerative diseases, which all remain without a cure.

















Expanded CAG/CTG repeats cause over 13 neurological and neuromuscular disorders, including Huntington disease, myotonic dystrophy, and several spinocerebellar ataxias. The diseases are debilitating, often leading to dementia. There is no available cure. Individually expanded repeat disorders are rare but together account for about 1 in 2000 people worldwide.

Our goal is to develop novel therapeutic avenues by targeting the unique features of expanded CAG/CTG repeats and to develop new technologies to detect (i.e., diagnose) and manipulate them. To achieve this, we use a variety of tools, including cutting edge molecular biology and genome engineering technologies, next-generation sequencing, as well as in vitro and in vivo pre-clinical disease models.

My laboratory has three main focal areas:

1) Gene editing and the mechanism of expanded CAG/CTG repeat instability

Expanded CAG/CTG repeats are highly unstable somatically, leading to mutation frequencies of 100% in some tissues. The size of the repeat tract determines in large part the severity of the disease. Understanding this mechanism is essential to designing and optimising treatments aimed at contracting the repeat tract.

We have recently developed a gene editing-based approach to contract the expanded repeat tract using the CRISPR-Cas9 system. We are currently determining whether this technology is applicable to contract and slow, prevent, or reverse the disease phenotypes in cells and in vivo. Moreover, we are studying the mechanisms of repeat contraction with the aim of improving the efficacy of inducing contractions.

Representative reference: Cinesi, C., Aeschbach, L., Yang, B. and Dion, V. (2016) Contracting CAG/CTG repeats using the CRISPR-Cas9 nickase. Nat Commun, 7, 13272.

2) The role of chromatin structure in the expression of expanded CAG/CTG repeats

Expanded CAG/CTG repeats accumulate chromatin marks reminiscent of heterochromatin and are downregulated (but not completely silenced) compared to normal size repeats. In addition, there is genetic and biochemical evidence that expanded repeats require extra factors for efficient expression. Identifying these factors and identifying their mode of action may lead to the development of epigenome editing approaches to combat expanded CAG/CTG repeat disorders.

We have developed a novel inducible chromatin targeting assay that allows us to determine which factors can change gene expression of expanded CAG/CTG repeats specifically. With this method, we can start to uncover a way forward to silence expanded repeats specifically.

Representative reference:

Yang B, Borgeaud AC, Aeschbach L, Rodríguez-Lima O, Ruiz Buendía GA, Cinesi C, Baubec T, Aeschbach L, Dion V. 2020. Expanded CAG/CTG Repeats Resist Gene Silencing Mediated by Targeted Epigenome Editing.BioRxiv.

Moreover, changes in chromatin marks is often associated with changes in higher order folding. We tested the prevalent hypothesis the expanded CAG/CTG repeats change chromatin folding, which impinges on repeat instability, changes in gene expression, and pathogenesis of Huntington's disease and myotonic dystrophy type 1. Using both molecular biology and bioinformatics, we find that this is not the case.

Representative reference:

Ruiz Buendía GA, Leleu M, Marzetta F, Vanzan L, Tan JY, Ythier V, Randall EL, Marques AC, Baubec T, Murr R, Xenarios I, Dion V. 2020. Three-dimensional chromatin interactions remain stable upon CAG/CTG repeat expansion. Science Advances. 6(27): eaaz4012

3) Development of tools to manipulate and detect expanded CAG/CTG repeats

Determining repeat size for diagnostic purposes and for routine molecular biology applications is laborious. This is because of the repetitive nature and the inherent heterogeneity of the repeat size from cell to cell (i.e., repeat instability). Thus, there is a great need to improve on the current technologies. In addition, such system will help us determine whether any therapies involving contracting the repeat tracts are effective.

Towards these goals, we are developing, in collaboration with the laboratory of Aurélien Bancaud (LAAS, France), microfluidics-based technologies for sizing expanded repeats. In addition, we have an ongoing collaboration with Ioannis Xenarios (UNIL, Switzerland) to develop sequencing-based approaches for these purposes.

Representative reference:

Malbec R†, Chami B†, Aeschbach L†, Ruiz Buendía GA, Socol M, Joseph P, Leïchlé T, Trofimenko E, Bancaud A*, Dion V*. 2019. µLAS: Sizing of expanded trinucleotide repeats with femtomolar sensitivity in less than 5 minutes. Scientific Reports. 9(1):23. †: co-first authors, *: co-corresponding authors


How to apply

Open positions will invariably be posted here.
Outstanding prospective PhD students and Postdocs who have or can attract their own fellowships are always welcome and should contact me.
Talented undergraduates and Master students are also welcome - contact me directly.

Guidelines to writing a cover letter for prospective PhD and postdocs

The goal of a cover letter is to convince the group leader to open your CV. No more, no less. Consequently, you need to keep it short (~250 words or less) and to the point. People are more likely to read something short. Your letter must contain the answer to two big questions:

  1. Why are you interested in this particular lab? This has to be as precise as possible. Broad answers to this questions, for example stating that you “want to join an outstanding institution”, are not compelling. Be specific. Why are you interested in our lab and not the lab next door? Why is the topic of the lab interesting to you? In other words, I want to know why you are applying to my lab and that you are not simply sending mass e-mails hoping that something will stick.
  2. What do you bring to the lab? This can be knowledge of a specific technique or field. Listing the techniques you are familiar with is not necessary as they should be in your CV, makes your cover letter longer, and generally does not help your case. Another way of phrasing this question is “What makes you stand out and be particularly well suited to join the lab?” It is not a problem if your area of expertise is outside that of the lab – it can be an advantage. But then you will have to emphasize why you are applying, which brings you back to why you are interested in this particular lab.

Some more tips:

  • Make the letter personal and custom-tailored. A good way to make the letter stand out is to explain the research topic of the lab in your own words. You will have to do it well (and briefly), however, as it can backfire if not done properly. Do not copy and paste from the lab’s website or papers.
  • Start the letter with why you are writing. Often letters start with “I am So and So from University X”. This is superfluous information as it is at the bottom of the e-mail and/or in your CV.
  • Writing a letter free of typos and grammatical mistakes is a good way to make a good first impression. Avoid overly flowery language (e.g., Dear Esteemed Sir) and using “Greetings” as an opening.
  • If you are responding to a job advert in the UK, the job descriptions are divided into essential and desirable criteria. To obtain an interview you have to meet all the essential criteria. In your cover letter, list verbetim the essential criteria and explain how you meet each one. It does not hurt to do so for the desirable criteria also. This makes the shortlisting easier and increases your chances of getting an interview. This part does not count towards the ~250 word guideline above, but it helps to keep it consice.

Quality and care in a letter will take you time, but it will make an enormous difference: many fewer requests will go unanswered. Remember that top labs want to hire passionate, motivated, and hard-working people. A well written letter should convey that you possess these qualities!

Current lab members

Ruqaiya Al Muharrami (Undergraduate) is an undergraduate at Cardiff University School of Biosciences aiming to graduate with a BSc in Biomedical Science in 2021. She is currently undertaking a Professional Training Year (PTY) in the Dion lab at Cardiff University, having started in October 2020. She hopes to gain first-hand experience in working in a research laboratory that will allow her to develop the skills required for a career in research.

Marcela Buricova (Research Assistant) completed her BSc in Biology and MSc in Animal Physiology at University of South Bohemia. During her BSc and MSc, she researched aging using the linden bug as a model. For her PhD, Marcela moved to the field of chronobiology as a part of the Marie Curie Initial Training Network Fellowship on Insect Timing (INsecTIME). The project was a collaboration between Prof. L.W. Beukeboom of the University of Groningen and Dr E. Tauber of the University of Leicester, studying light synchronisation of circadian and seasonal rhythms in the parasitic wasp Nasonia vitripennis. After a short Lab Manager role at the MRC London School of Medical Sciences in the Cochemé Redox Metabolism group, she joined the lab in Cardiff as a Research Assistant.

Alys Evans (Postdoc/Research Associate) completed a BSc in Biochemistry at the University of Southampton. Following this, she obtained a PhD in Cancer and Genetics at Cardiff University under the supervision of Professor Duncan Baird and Dr Kate Liddiard. Her project introduced her to DNA repair, focussing on the role of DNA polymerase theta (POLQ) in telomeric stability. Alys is excited to join the Dion lab where she aims to expand her understanding within the field of chromatin structure by studying its effect on the expression and stability of expanded CAG/CTG repeats.

Florence Gidney (Research Assistant) completed her BSc in Biomedical Sciences in 2016 from the University of Southampton, where she completed a laboratory research project on the multidrug resistance protein 1, its mechanism of action, and pharmaceutical methods of inhibiting the protein. She has recently completed a Master’s degree in Neuroimaging from Cardiff University, her thesis focussing on central obesity and its association with impaired white matter microstructure in key areas known to be damaged in late-onset Alzheimer’s Disease. Now you can find her wandering the lab, singing, much to the dismay of her colleagues. 

Laura Heraty (PhD Student) completed her BSc in Biochemistry and Genetics from the University of Sheffield in June 2018. She then went on to undertake a MSc in Translational Neuropathology at the same university but within the Sheffield Institute for Translational Neuroscience (SITraN), which she completed in August 2019. Her project focused on Motor Neuron Disease, specifically focusing on the role of microglia in the disease. In the Dion lab, she is working on the mechanism of contractions of expanded CAG/CTG repeats.

Eleanor Heuchan (Undergraduate) is undergraduate with the Cardiff University School of Biosciences. I am hoping to graduate with a BSc in Neuroscience in 2022. I am currently undertaking a Professional Training Year (PTY) at the Dion lab, having started in October 2020. I am working on bioinformatics projects supervised by Alysha Taylor. I hope to make a meaningful contribution to the Dion lab's important research whilst also developing new skills that will be essential to my future career.

Meghan Larin (Postdoc/Research Associate) grew up in Ontario, Canada. In the early part of her career she completed a BSc in biochemistry at the University of Waterloo and an MSc in biomedical sciences and toxicology at the University of Guelph. Following this, she obtained a PhD in pharmacology and toxicology at the University of Toronto under the supervision of Dr J Peter McPherson. Her project, which introduced her to mechanisms of genomic stability and DNA repair, focused on the characterisation of a novel mouse model of the disease Fanconi Anemia. More recently, Meghan specialised further by pursuing a postdoctoral position with Dr Stephen West at Clare Hall Laboratories, Hertfordshire, latterly part of the Francis Crick Institute, London. Her project focused on the role of structure specific endonucleases in the formation of chromothriptic chromosomes originating from micronuclei. Meghan is excited to now be part of the Dion lab and aims to apply her knowledge of genomic stability and mechanisms of DNA repair to the study of trinucleotide repeat disorders.

Antoine Mangin (Staff PhD Student) obtained his master’s degree in Paris at EPHE in 2019. During this time, he worked for 2 years in the laboratory of Dr Genevieve Gourdon at Imagine Institute in Paris and also 5 months in our lab in Lausanne. His first study was about repeat size and content in atypical DM1 families. He then studied the mechanism of contraction of expanded triplet repeats. He's has been a Senior technician since Oct. 2019, but is set to start a PhD in the lab in January of 2020. He will be developing new tools to promote contractions of expanded triplet repeats.

Alvaro Murillo (Postdoc / Research Associate) obtained his bachelor in biology at the University of Salamanca, with specialization in fundamental biology and biotechnology. After that, he obtained his master’s degree in Cancer Biology in 2014 at the same university. For 3 years he worked on autophagy activation to remove Huntington´s disease cell aggregates. Later, he started his PhD project under the direction of Isabel Perez-Otano and Sonia Marco at the University of Navarra for two years. The lab then moved to the Neuroscience Institute of Alicante. His project focused on in vivo silencing of GluN3A-containing NMDAR by striatal AAV-shRNA injection witch rescue HD symptoms. Also he studied deeply the expression of GluN3A in neuronal network refinement critical period. Alvaro joined Vincent's laboratory in February 2020 where he is very enthusiastic to apply and increase his knowledge of CAG/CTG repeat diseases. He hopes dominate gene editing as much as old-Spanish language.

Emma Randall (Research Assistant) obtained her BSc in Biology and then MRes in Ecology, Evolution and Conservation at Imperial College London. She went to take on the world of insecticide resistance as a research assistant at Rothamsted Research, then at the University of Exeter. In April 2019, she was warmly welcomed into the fold of the Dion lab at Cardiff University.

Christoff Smith (Senior Technician) completed his BSc (Hons) in Biology at the University of Glamorgan and has worked as a technician and research assistant in both academia and the NHS. Although the wet-lab bench is his second home, he has a growing interest in coding, bioinformatics, and data science. Recently he was lucky enough to join the Dion Group, where he finds himself surrounded by younger, smarter, more-gifted colleagues. But he has a quiet wisdom that comes only with age.

Alysha Taylor (Bioinformatician) completed her B.Sc in Genetics and Cell Biology from Dublin City University in 2016. For her PhD, Alysha investigated the role of regulatory and protein coding innovation in the evolution of mammal placenta at the University of Leeds. Jointly supervised by Dr Mary J O'Connell and Dr Niamh Forde, Alysha combined lineage-specific selective pressure analyses and miRNA identification across multiple genomes to investigate novel mammalian regulatory networks. In addition, she gained experience translating computational data to experimental analyses, investigating expression patterns of mammalian miRNAs and miRNA targets of interest to identify regulatory networks implicated in remodelling the mammalian endometrium during early pregnancy. While at the University of Leeds, Alysha was involved in the LeedsOmics virtual research institute, acted as a representative for the Research Computing facility at the University of Leeds and assisted on a number of courses teaching bioinformatics techniques. At the Dion lab, Alysha is analysing sequencing data from expanded and contracted CAG/CTG repeats, off-target mutations and all other data she can get her hands on.

Past projects

Former lab members

PhD students:

Gustavo Ruiz Buendia: Feb 2016 to Jan 2020 – now a Bioinformatician for the Swiss Institute of Bioinformatics (CH).

Cinzia Cinesi: March 2015 to June 2019 - now a Gene therapy project manager at DiNAQOR in Zurich, Switzerland.

Bin Yang: Oct. 2013 to Sept 2018 – now a consultant for Alcimed in Cologne, Germany.


Oscar Rodriguez Lima: May 2016 to August 2018 – now a Dad in Mexico City.

Master Students:

Roman Mizeret - July 2019 to May 2020 - now a PhD student in David Suter's lab at EPFL (CH).

Antoine Mangin – Sept. 2018 to Jan 2019 – now PhD student in our lab.

Dinis Barros - Feb 2018 to May 2019 - now a PhD student with Jolanda van Leeuwen at UNIL (CH).

Nastassia Gobet - Feb. 2017 to May 2018 – now a PhD student with Paul Franken at UNIL (CH).

Paula Barszcz – Feb. 2016 to Jan. 2017 – now a Regular Front-end Developer w First Data Corporation in Warsaw, Poland.

Alicia Borgeaud – Feb. 2016 to May 2017 – now a PhD student with Wanda Kukulski at the LMB in Cambridge, UK.

Evgeniya Trofimenko – Feb. 2015 to Jan. 2016 – now a PhD student with Christian Widman at UNIL (CH).

Gustavo Ruiz Buendia - Feb. 2015 to Jan 2016 – now a Bioinformatician for the Swiss Institute of Bioinformatics (CH).

Cinzia Cinesi - Feb. 2014 - Jan 2015 - now a Gene therapy project manager at DiNAQOR in Zurich, (CH).

Undergraduate Students:

Elliot Gibbons - Sept 2019 to Sept 2020 – now an undergraduate student at Cardiff University (UK).

Romane Mizeret – Aug. to Sept. 2017  and Aug. to Sept 2018 – now a PhD student in David Suter's lab at EPFL (CH).

Johanna E. Martin – Jul. to Aug. 2016 – now a PhD student with Karim Labib at the University of Dundee (UK).

Waad Al-Bawardi – Jul. to Aug. 2014 – now a PhD Student with Nick Gilbert at the University of Edinburgh (UK).


Karim Bouvet - Research Assistant from Oct 2018 to Sept 2019.

Flavia Marzetta - Bioinformatician from June 2017 to June 2018 - now part of the Swiss Institute of Bioinformatics.

Lorène Aeschbach – Senior Technician from Dec. 2013 to Jan 2019 – now a senior technician in Hilal A. Lashuel at the EPFL (CH).

Antonia Feola – Visiting PhD student from Oct. to Dec. 2014 – now a Scientific Researcher at Università degli Studi di Napoli Federico II (IT).

Marie Sgandurra – Research Assistant from Dec. 2013 to Jun. 2014 – now a Lead Laboratory Technician with Philip Moris International (CH).