Translesion synthesis

MAD2L2 – as a member of the shieldin complex - counteracts resection during DNA repair. Here the authors demonstrate that MAD2L2 protects stalled replication forks from excessive resection, in a shieldin-independent and REV3L-dependent manner.

This manuscript elucidates new mechanisms of mutagenesis in mycobacteria by implicating two translesion DNA polymerases in genome diversification, including creating the mutations that underlie all antibiotic resistance in these global pathogens.

New data show that the HMCES protein suppresses DNA double-strand break formation by cross-linking to and thereby stabilizing an abasic site generated during replication-coupled repair of a DNA interstrand cross-link, thus demonstrating a physiological role of HMCES in DNA repair.

The structure of mismatched DNA-Polζ ternary complex provides a basis for understanding what makes Polζ adept at extending DNA synthesis past mismatched base pairs.

Loss of BRCA1 or BRCA2 results in genomic instability; however most studies have focused on the role of these proteins in double-strand break repair. Here the authors coupled cell line genetics and whole genome sequencing to investigate the formation of base substitutions and short indels in BRCA1-deficient cells, revealing a role for translesion DNA synthesis regulated by 53BP1.

The human DNA primase and DNA polymerase PrimPol replicates through the major oxidative DNA damage lesion 7,8-dihydro-8-oxoguanine (oxoG) via translesion synthesis in a mostly error-free manner thus suppressing oxoG-induced mutagenesis in mitochondria and the nucleus. Here, the authors present crystal structures of PrimPol in complex with an oxoG lesion in different contexts that provide mechanistic insights into how PrimPol performs predominantly accurate synthesis on oxidative-damaged DNAs in human cells.