Project #16898
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#16898 : PacBio sequencing of DM1 cells treated with a TALEN
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Name of Applicant : Guy-Franck RICHARD
Date of application : 15-04-2021
Unit : Dynamics of the Genome
Location : Fernbach 4ème étage
Phone : 0140618436
@ Mail :

Project context and summary :

Myotonic dystrophy type 1 (DM1 or Steinert disease) is a monogenic neurodegenerative disorder due to the expansion of a CTG trinucleotide repeat in the 3' UTR of the DMPK gene on chromosome 19. We developed a strategy to induce a DNA double-strand break (DSB) within the expanded repeat in order to contract it below the pathological range in humans. This approach was successful in yeast and mouse cells and we are now trying to apply it to human cells from a patient affected by DM1. This patient was diagnosed with a large CTG repeat expansion (≈ 2000 triplets) and we estimated the size of the repeat tract by Southern blot to be 1980 triplets. These cells (ASA cells) were immortalized by overexpression of the telomerase catalytic unit, theoretically allowing to grow them for 100 generations (instead of ca. 20 generations for primary cells). A TALEN directed to the expanded CTG repeat was expressed in ASA cells for several weeks and the population was subcloned. Trinucleotide repeat length was analyzed in many clones, by Southern blotting. This showed that the repeat was partially contracted in most clones, the others showing no size change (or a small expansion). Ten clones were chosen to be sequenced by PacBio, in addition to a non-treated ASA clone that will be used as the reference for future work on ASA cells.

Related team publications :
G.-F. Richard (2015) Shortening trinucleotide repeats using highly specific endonucleases : a possible approach to gene therapy ? Trends in Genetics 31 : 177-186
V. Mosbach, L. Poggi, D. Viterbo, M. Charpentier and G.-F. Richard (2018) TALEN-induced double-strand break repair of CTG trinucleotide repeats. Cell Reports 22: 2146-2159
V. Mosbach, D. Viterbo, S. Descorps-Declère, L. Poggi, W. Vaysse-Zinkhöfer, and G.-F. Richard (2020) Resection and repair of a Cas9 double-strand break at CTG trinucleotide repeats induces local and extensive chromosomal rearrangements. PLoS Genetics 16: e1008924
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Status : Declined

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