Work

Genome-wide analysis of DNA-PK-bound MRN cleavage products supports a sequential model of DSB repair pathway choice

Year: 2023

Type: article

Abstract: The Mre11-Rad50-Nbs1 (MRN) complex recognizes and processes DNA double-strand breaks for homologous recombination by performing short-range removal of 5' strands. Endonucleolytic processing by MRN requires a stably bound protein at the break site-a role we postulate is played by DNA-dependent protein kinase (DNA-PK) in mammals. Here we interrogate sites of MRN-dependent processing by identifying sites of CtIP association and by sequencing DNA-PK-bound DNA fragments that are products of MRN cleavage. These intermediates are generated most efficiently when DNA-PK is catalytically blocked, yielding products within 200 bp of the break site, whereas DNA-PK products in the absence of kinase inhibition show greater dispersal. Use of light-activated Cas9 to induce breaks facilitates temporal resolution of DNA-PK and Mre11 binding, showing that both complexes bind to DNA ends before release of DNA-PK-bound products. These results support a sequential model of double-strand break repair involving collaborative interactions between homologous and non-homologous repair complexes.

Source: Nature Communications

DOI: 10.1038/s41467-023-41544-8

Authors: Rajashree A. Deshpande, Alberto Marin-Gonzalez, Hannah K. Barnes, Phillip R. Woolley, Taekjip Ha, Tanya T. Paull

Institutions: Howard Hughes Medical Institute, Johns Hopkins University, Johns Hopkins Medicine, The University of Texas at Austin

Language: English

Topic: DNA Repair Mechanisms

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $6,290