The molecular basis of transcription-coupled DNA repair
Second Supervisor: Prof Chris Schofield
How some important forms of DNA damage are repaired in non-dividing cells remains poorly understood. This includes DNA interstrand crosslinks (ICLs) -- a highly toxic form of damage produced spontaneously in our cells, but also by several important anticancer drugs. ICLs sustained through endogenous DNA damage in non-dividing cells must be repaired accurately; failure to accurately repair such damage causes genomic changes precipitating malignant transformation, loss of cell function/viability and ageing. Moreover, it is now widely accepted that tumours contain subset(s) of cells that play a key role in populating the highly proliferative tumour mass, acting in a stem cell-like capacity. Such cells are more resistant to ICL-inducing chemotherapeutics than the bulk tumour population, can persist even after all detectable disease is apparently eradicated, and their persistence is a likely cause of relapse. Targeting this subpopulation of cells warrants significant attention; from both cancer cause/prevention and treatment perspectives understanding ICL repair in non-dividing cells is a pressing issue. We have recently discovered that in non-dividing cells, all lCL repair is transcription-coupled (TC), a process termed TC-ICL repair. Here, we will elucidate the molecular basis of this poorly understood repair pathway. While we have already identified several of the key factors required for TC-ICL repair, we will undertake a genetic (CRISPR) screen for novel candidate TC-ICL repair factors using a recently developed a functional assay. Using genomics methods we will validate the factors discovered in the screen and employ multiple cell biology techniques to obtain a complete picture of TC-ICL repair biology. This will be complemented with biochemical studies, reconstituting and structurally characterising TC-ICL repair. We have programmes to discover inhibitors of several of the known TC-ICL repair factors and the student will help to iteratively improve these. Together, we aim for a complete molecular characterisation of the ICL-TCR repair reaction.
We combine cell biology (including advanced light microscopy), cellular genetics (including genome editing) and biochemistry (including cryo-electron microscopy) to provide a detailed understanding of key DNA repair pathways that are targets for cancer prevention and treatment.
Shen, S., Vagner, S. and Robert, C., 2020. Persistent cancer cells: the deadly survivors. Cell, 183(4), pp.860-874.