Catalytic and non-catalytic functions of DNA polymerase kappa in translesion DNA synthesis

ABSTRACT: Translesion DNA synthesis (TLS) is a cellular process that enables the bypass of DNA lesions encountered during DNA replication and is emerging as a primary target of chemotherapy. Among vertebrate DNA polymerases, polymerase kappa (PolK) has the distinctive ability to bypass minor groove DNA adducts in vitro. However, PolK is also required for cells to overcome major groove DNA adducts but the basis of this requirement is unclear. Here, we combine CRISPR base editor screening technology in human cells with TLS analysis of defined DNA lesions in Xenopus egg extracts to unravel the functions and regulations of PolK during lesion bypass. Strikingly, we show that PolK has two main functions during TLS, which are differentially regulated via Rev1 binding. On the one hand, PolK is essential to replicate across a minor groove DNA lesion in a process that depends on PCNA ubiquitylation but is independent of Rev1. On the other hand, via its cooperative interaction with Rev1 and ubiquitylated PCNA, PolK appears to stabilize the Rev1-PolZ extension complex on DNA to allow extension past major groove DNA lesions and abasic sites, in a process that is independent of PolK's catalytic activity. Together, our work identifies catalytic and non-catalytic functions of PolK in TLS and reveals important regulatory mechanisms underlying the unique domain architecture present at the C-terminal end of Y-family TLS polymerases.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Xenopus Laevis (african Clawed Frog)

TISSUE(S): Egg

SUBMITTER: Ivo Hendriks  

LAB HEAD: Ivo Hendriks

PROVIDER: PXD044258 | Pride | 2024-08-27

REPOSITORIES: Pride