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bioRxiv · 10.1101/2020.05.09.085902

Bypass of DNA Interstrand crosslinks by a Rev1-DNA polymerase ζ complex

Buch, R. B.·Cheun, Y. K.·Roy, U.·Schärer, O. D.·Burgers, P. M.
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Abstract

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

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Buch, R. B., Cheun, Y. K., Roy, U., Schärer, O. D., Burgers, P. M.. 2020-05-10. Bypass of DNA Interstrand crosslinks by a Rev1-DNA polymerase ζ complex. https://doi.org/10.1101/2020.05.09.085902

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