Julian SALE, MRC Laboratory of Molecular Biology, Cambridge UK

The ability of certain DNA sequences to form secondary structures means that DNA itself can pose on of the most potent barriers to its own replication. By harnessing the fact that impediments to processive replication can lead to local, heritable loss of epigenetic information, we are able to monitor episodes of in vivo replication pausing at defined sequences, for example those able to form G-quadruplexes and triplexes, with exquisite sensitivity (Schiavone et al., 2014; Schiavone et al., 2016; Guilbaud et al., 2017). Our recent work suggests that even short sequences with structure-forming potential that were previously not thought to impede replication actually do cause transient polymerase stalling (Šviković et al., 2019). My talk will focus on the mechanisms that ensure replication through these sequences, preventing more deleterious genetic consequences. I will also discuss unpublished data exploring the relationship between sequence, structure formation and the response of a model polymerase. I will show how the response of a polymerase in a simple primer extension assay can make predictions about the structure that a given sequence forms and that this correlates with the extent to which the sequence is maintained or mutated in the genome during evolution. The data suggest how relatively simple replication parameters may determine the genome wide distribution and stability of short tandem repeats.

References

Guilbaud, G., Murat, P., Recolin, B., Campbell, B. C., Maiter, A., Sale, J. E., and Balasubramanian, S. (2017). Local epigenetic reprogramming induced by G-quadruplex ligands. Nat Chem 9, 1110-1117.
Schiavone, D., Jozwiakowski, S. K., Romanello, M., Guilbaud, G., Guilliam, T. A., Bailey, L. J., Sale, J. E., and Doherty, A. J. (2016). PrimPol Is Required for Replicative Tolerance of G Quadruplexes in Vertebrate Cells. Mol Cell 61, 161-169.
Schiavone, D., Guilbaud, G., Murat, P., Papadopoulou, C., Sarkies, P., Prioleau, M.-N., Balasubramanian, S., and Sale, J. E. (2014). Determinants of G quadruplex-induced epigenetic instability in REV1-deficient cells. The EMBO Journal 33, 2507-2520.
Šviković, S., Crisp, A., Tan-Wong, S. M., Guilliam, T. A., Doherty, A. J., Proudfoot, N. J., Guilbaud, G., and Sale, J. E. (2019). R-loop formation during S phase is restricted by PrimPol-mediated repriming. EMBO J 38,

Julian E. Sale
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, U.K.
Email: jes@mrc-lmb.cam.ac.uk

Contact : Vincent Vanoosthuyse