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Yr Athro Vincent Dion

Yr Athro Vincent Dion

Professor, Dementia Research Institute

Yr Ysgol Meddygaeth

+44(0)29 2251 0893
1.03 - Office J, Adeilad Hadyn Ellis, Heol Maendy, Caerdydd, CF24 4HQ
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We are interested in (epi)genome editing at expanded CAG/CTG repeats. These unusual sequences cause 14 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 A, Aeschbach L, Dion V. (2018) Uncovering the interplay between epigenome editing efficiency and sequence context using a novel inducible targeting system. BioRxiv.

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.

How to apply

We are always on the lookout for outstanding PhD students and Postdocs who have or can attract their own fellowships. Open positions will invariably be posted here. 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.

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!

Prosiectau ymchwil ôl-raddedig

Current lab members

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.

Cinzia Cinesi (PhD student) obtained her Bachelor in Biology from the Università dell'Insubria in Varese in 2013, where she did her research thesis on Phylogenetic characterization of Salmo trutta macrostigma in SIC Monte Arcosu, in the lab of Serena Zaccara. After a First step Master’s project in the lab of Nouria Hernandez, she joined our group in Feb 2014 for her full Master’s research project. She stayed as a PhD student and graduated in June of 2020.

Elliot Gibbons (Undergraduate) is a BIOSCI undergraduate studying at Cardiff University. He is currently undertaking a Placement Training Year (PTY), having started in the lab in September 2019.  He hopes to graduate with a Biochemistry BSc in 2021, having gained valuable practical experience working in the lab.

Florence Gidney (Senior Technician) 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. 

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.

Emma Randall (Senior Technician) 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.

Gustavo Ruiz Buendia (PhD Student) did his undergraduate studies in Genomic Sciences at the National Autonomous University of Mexico. During that period, he spent a year in Cold Spring Harbor Lab in the group of David Spector, near the unparalleled NYC. After a Master’s in the lab, he has been a PhD student since Feb 2016. If he could go back in time, he would like to be a professional tennis player. Until that’s feasible, he’s delighted to investigate the wonderful world of nuclear organization!

Former lab members

PhD students:

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


Oscar Rodriguez Lima: May 2016 to August 2018 – now looking for new opportunities. Now a trainee with Bart Deplancke at the EPFL (CH).

Master Students:

Antoine Mangin – Sept. 2018 to Jan 2019 – now completing his MSc - co-direction with Stéphanie Tomé at Institut Imagine (FR).

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 Junior Front-end Developer with APPLICA.AI 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).

Undergraduate Students:

Romane Mizeret – Aug. to Sept. 2017  and Aug. to Sept 2018 – now a Master student in our lab - registered at UNIL (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 - now looking for new opportunities.

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 biologist at Azienda Ospedaliera Santa Maria di Terni (IT).

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