Bypass of DNA interstrand crosslinks by a Rev1-DNA polymerase ? complex.

ABSTRACT: DNA polymerase ? (Pol ?) and Rev1 are essential for the repair of DNA interstrand crosslink (ICL) damage. We have used yeast DNA polymerases ?, ? and Rev1 to study translesion synthesis (TLS) past a nitrogen mustard-based interstrand crosslink (ICL) with an 8-atom linker between the crosslinked bases. The Rev1-Pol ? complex was most efficient in complete bypass synthesis, by 2-3 fold, compared to Pol ? alone or Pol ?. Rev1 protein, but not its catalytic activity, was required for efficient TLS. A dCMP residue was faithfully inserted across the ICL-G by Pol ?, Pol ?, and Rev1-Pol ?. Rev1-Pol ?, and particularly Pol ? alone showed a tendency to stall before the ICL, whereas Pol ? stalled just after insertion across the ICL. The stalling of Pol ? directly past the ICL is attributed to its autoinhibitory activity, caused by elongation of the short ICL-unhooked oligonucleotide (a six-mer in our study) by Pol ? providing a barrier to further elongation of the correct primer. No stalling by Rev1-Pol ? directly past the ICL was observed, suggesting that the proposed function of Pol ? as an extender DNA polymerase is also required for ICL repair.

SUBMITTER: Bezalel-Buch R 

PROVIDER: S-EPMC7470978 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature