Fumiko Esashi

Genome Stability and Cell Cycle

Our research goal is to elucidate how proliferating human cells safeguard their genomic DNA against various stresses coming from the environment (e.g., radiation, genotoxic agents) and from normal processes of cell growth (e.g., DNA replication, transcription & mitotic chromosome dynamics).

Accumulation of Rad51 at sites of DNA damage and Rad51-mediated HR

Factors contributing to the recruitment of Rad51

We are particularly interested in homologous recombination (HR), a repair mechanism which is catalysed by the evolutionarily conserved RecA-family recombinase RAD51. HR normally takes place during S and G2 phases of the cell cycle and, by using the replicated sister DNA as a repair template, can faithfully recover the missing genomic information. However, if HR wrongly uses a similar but non-allelic DNA as a repair template, regions of genomic DNA can be amplified, deleted or exchanged. Such non-allelic HR events could result in genome instability, but could conversely offer, in some situations, structural or functional robustness.

Genome size has increased enormously during evolution, with more than 50% of the human genome being repetitive. Reflecting this increased complexity, our genome encodes more recently evolved HR regulators, such as BRCA2 (breast cancer, 2) and PALB2 (partner and localiser of BRCA2). In humans, mutations of these HR regulators contribute to the development of various genome instability syndromes, including familial cancers and Fanconi anaemia, highlighting the importance of HR regulation.

We aim to understand how these HR regulators (e.g. BRCA2, PALB2 and beyond) coordinate their actions to control HR in the context of the cell cycle and at regions of genomic DNA that are prone to break or recombine. We take a multidisciplinary approach that includes molecular and cellular biology, genetics, biochemistry, proteomics and next-generation sequencing.

Relevant Publications

Wassing E.I., Saayman X., Rampazzo L., Ralf C., Bassett A. & Esashi F.
2021

Nature Communications 12: 5380

Paoletti F., Johnson E., El-Sagheer A., Brown T., Dushek O., & Esashi F.
2020

EMBO Journal 39: e103002

Bleuyard J.Y., Fournier M., Nakato R., Couturier A.M., Katou Y., Ralf C., Hester S.S., Dominguez D., Rhodes D., Humphrey T.C., Shirahige K. & Esashi F
2017

Proc Natl Acad Sci U S A. 114: 7671-7676

Yata K., Bleuyard JY, Nakato R, Ralf C., Katou Y, Schwab R., Niedzwiedz W., Shirahige K, Esashi F.
2014

Cell Rep 7: 1547-59

Yata, K, Lloyd, J., Maslen, S., Bleuyard, J.Y., Skehel, M., Smerdon, S. J., Esashi, F
2012

Mol. Cell 45: 371-83

Bleuyard J.Y., Buisson R., Masson J.Y. & Esashi F.
2012

EMBO Reports. 13: 35-41