Nature Communications: DNA binding and RAD51 engagement by the BRCA2 C-terminus orchestrate DNA repair and replication fork preservation (Sung Lab)

Youngho Kwon,
Heike Rösner,
Weixing Zhao,
Platon Selemenakis,
Zhuoling He,
Ajinkya S. Kawale,
Jeffrey N. Katz,
Cody M. Rogers,
Francisco E. Neal,
Aida Badamchi Shabestari,
Valdemaras Petrosius,
Akhilesh K. Singh,
Marina Z. Joel,
Lucy Lu,
Stephen P. Holloway,
Sandeep Burma,
Bipasha Mukherjee,
Robert Hromas,
Alexander Mazin,
Claudia Wiese,
Claus S. Sørensen &
Patrick Sung

Abstract

The tumor suppressor BRCA2 participates in DNA double-strand break repair by RAD51-dependent homologous recombination and protects stressed DNA replication forks from nucleolytic attack. We demonstrate that the C-terminal Recombinase Binding (CTRB) region of BRCA2, encoded by gene exon 27, harbors a DNA binding activity. CTRB alone stimulates the DNA strand exchange activity of RAD51 and permits the utilization of RPA-coated ssDNA by RAD51 for strand exchange. Moreover, CTRB functionally synergizes with the Oligonucleotide Binding fold containing the DNA binding domain and BRC4 repeat of BRCA2 in RPA-RAD51 exchange on ssDNA. Importantly, we show that the DNA binding and RAD51 interaction attributes of the CTRB are crucial for homologous recombination and protection of replication forks against MRE11-mediated attrition. Our findings shed light on the role of the CTRB region in genome repair, reveal the remarkable functional plasticity of BRCA2, and help explain why deletion of Brca2 exon 27 impacts upon embryonic lethality.

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