Polymerase ?-helicase efficiently unwinds DNA and RNA-DNA hybrids.

ABSTRACT: POLQ is a unique multifunctional replication and repair gene that encodes for a N-terminal superfamily 2 helicase and a C-terminal A-family polymerase. Although the function of the polymerase domain has been investigated, little is understood regarding the helicase domain. Multiple studies have reported that polymerase ?-helicase (Pol?-helicase) is unable to unwind DNA. However, it exhibits ATPase activity that is stimulated by single-stranded DNA, which presents a biochemical conundrum. In contrast to previous reports, we demonstrate that Pol?-helicase (residues 1-894) efficiently unwinds DNA with 3'-5' polarity, including DNA with 3' or 5' overhangs, blunt-ended DNA, and replication forks. Pol?-helicase also efficiently unwinds RNA-DNA hybrids and exhibits a preference for unwinding the lagging strand at replication forks, similar to related HELQ helicase. Finally, we find that Pol?-helicase can facilitate strand displacement synthesis by Pol?-polymerase, suggesting a plausible function for the helicase domain. Taken together, these findings indicate nucleic acid unwinding as a relevant activity for Pol? in replication repair.

SUBMITTER: Ozdemir AY 

PROVIDER: S-EPMC5892577 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature