2.  REPLICATION AND REPAIR OF ENDOGENOUS LESIONS

  

2.1. SMC5/6 roles in natural pausing sites replication and repair.

Previously we uncovered a role for budding yeast Smc5/6 in promoting replication through natural pausing sites, NPSs (Menolfi et al, Mol Cell, 2015). Using genetic screens, we identified factors that are synthetic lethal with Smc5/6 deregulation and which co-localize with Smc5/6 genome-wide and at NPSs. We study the interplay between Smc5/6 and these factors in replication and repair of endogenous lesions.

Team members: Sumedha Agashe, Matteo Villa

  

2.2. SMC5/6 and DDX11 roles in repairing (ICLs).

We found that knockout/knockdown of SMC5/6 in avian DT40 and HeLa cells causes hypersensitivity towards intra- and inter-strand crosslinkers (ICLs). Of interest, SMC5/6 components physically interact with FANCD2-I in human cells and deregulation of SMC5/6 is epistatic with mutations affecting Fanconi anemia (FA) regarding ICL repair efficiency (Rossi et al, EMBO Reports, 200). Moreover, we found that SMC5/6 functions jointly with DDX11(Rossi et al, EMBO Reports, 200), which functions as a backup pathway for Fanconi anemia in the repair of ICLs and metabolic formaldehyde (Abe et al, PNAS, 2018). We are further investigating the roles of SMC5/6 and DDX11 in the replication fork response and cellular ability to replicate in the presence of ICLs.

Team members: Nanda Kumar Jegadesan, Alessandro Morea  

  

2.3. DDX11 roles in facilitating replication through abasic sites. We uncovered that DDX11 facilitates replication through abasic sites formed at the immunoglobulin gene variable locus in DT40 vertebrate cells (Abe et al., PNAS, 2018). We are exploring if the mutagenic role of DDX11 is observed genome-wide and if it is manifested in response to overexpression of other APOBEC enzymes that induce abasic sites.

Team members: Ryotaro Kawasumi