Repair of G-quadruplex DNA Facilitated by the FANCJ Helicase and the REV1 Polymerase

Abstract

G-quadruplexes (G4s) are DNA structures formed by guanine-rich nucleic acids. Damaged G4s can interfere with essential cellular processes. The FANCJ helicase facilitates DNA replication through G4-forming regions. In a previous study, an “AKKQ” amino acid motif was identified within FANCJ helicase that targets G4 structures. In this project the primary aim is to test a model in which FANCJ recruits the REV1 repair protein to rescue a G4 DNA site. The approach is to first purchase FANCJ peptides and G4 DNA oligos, purify REV1 CTD and hPCNA, and then use binding experiments to measure their association reactions with each other as well as with various DNA types. The binding results thus far show that FANCJ targets a stalled replication fork at a G4-containing DNA site, and then recruits REV1 to efficiently replicate DNA across from a G-quadruplex. In the future, the plan is to reconstitute these reactions in human cells to further assess the validity of this model.