Single strand gap repair: The presynaptic phase plays a pivotal role in modulating lesion tolerance pathways.

Autor: Luisa Laureti, Lara Lee, Gaëlle Philippin, Michel Kahi, Vincent Pagès
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: PLoS Genetics, Vol 18, Iss 6, p e1010238 (2022)
Druh dokumentu: article
ISSN: 1553-7390
1553-7404
DOI: 10.1371/journal.pgen.1010238
Popis: During replication, the presence of unrepaired lesions results in the formation of single stranded DNA (ssDNA) gaps that need to be repaired to preserve genome integrity and cell survival. All organisms have evolved two major lesion tolerance pathways to continue replication: Translesion Synthesis (TLS), potentially mutagenic, and Homology Directed Gap Repair (HDGR), that relies on homologous recombination. In Escherichia coli, the RecF pathway repairs such ssDNA gaps by processing them to produce a recombinogenic RecA nucleofilament during the presynaptic phase. In this study, we show that the presynaptic phase is crucial for modulating lesion tolerance pathways since the competition between TLS and HDGR occurs at this stage. Impairing either the extension of the ssDNA gap (mediated by the nuclease RecJ and the helicase RecQ) or the loading of RecA (mediated by RecFOR) leads to a decrease in HDGR and a concomitant increase in TLS. Hence, we conclude that defects in the presynaptic phase delay the formation of the D-loop and increase the time window allowed for TLS. In contrast, we show that a defect in the postsynaptic phase that impairs HDGR does not lead to an increase in TLS. Unexpectedly, we also reveal a strong genetic interaction between recF and recJ genes, that results in a recA deficient-like phenotype in which HDGR is almost completely abolished.
Databáze: Directory of Open Access Journals
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