Self-reversal facilitates the resolution of HMCES DNA-protein crosslinks in cells

Autor: Jorge Rua-Fernandez, Courtney A. Lovejoy, Kavi P.M. Mehta, Katherine A. Paulin, Yasmine T. Toudji, Celeste Giansanti, Brandt F. Eichman, David Cortez
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Cell Reports, Vol 42, Iss 11, Pp 113427- (2023)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2023.113427
Popis: Summary: Abasic sites are common DNA lesions stalling polymerases and threatening genome stability. When located in single-stranded DNA (ssDNA), they are shielded from aberrant processing by 5-hydroxymethyl cytosine, embryonic stem cell (ESC)-specific (HMCES) via a DNA-protein crosslink (DPC) that prevents double-strand breaks. Nevertheless, HMCES-DPCs must be removed to complete DNA repair. Here, we find that DNA polymerase α inhibition generates ssDNA abasic sites and HMCES-DPCs. These DPCs are resolved with a half-life of approximately 1.5 h. HMCES can catalyze its own DPC self-reversal reaction, which is dependent on glutamate 127 and is favored when the ssDNA is converted to duplex DNA. When the self-reversal mechanism is inactivated in cells, HMCES-DPC removal is delayed, cell proliferation is slowed, and cells become hypersensitive to DNA damage agents that increase AP (apurinic/apyrimidinic) site formation. In these circumstances, proteolysis may become an important mechanism of HMCES-DPC resolution. Thus, HMCES-DPC formation followed by self-reversal is an important mechanism for ssDNA AP site management.
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