Two RecA orthologs, Rad51 and Dmc1, mediate homologous recombination in meiotic cells. During budding yeast meiosis, Hed1 coordinates the actions of Rad51 and Dmc1 by down-regulating Rad51 activity. It is thought that Hed1-dependent attenuation of Rad51 facilitates formation of crossovers that are necessary for the correct segregation of chromosomes at the first meiotic division. We purified Hed1 in order to elucidate its mechanism of action. Hed1 binds Rad51 with high affinity and specificity. We show that Hed1 does not adversely affect assembly of the Rad51 presynaptic filament, but it specifically prohibits interaction of Rad51 with Rad54, a Swi2/Snf2-like factor that is indispensable for Rad51-mediated recombination. In congruence with the biochemical results, Hed1 prevents the recruitment of Rad54 to a site-specific DNA double-strand break in vivo but has no effect on the recruitment of Rad51. These findings shed light on the function of Hed1 and, importantly, unveil a novel mechanism for the regulation of homologous recombination.
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http://dx.doi.org/10.1101/gad.1638708 | DOI Listing |
Int J Biol Sci
December 2024
NHC Key Laboratory of Carcinogenesis, Hunan Key Laboratory of Oncotarget Gene, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410078, China.
DNA Repair (Amst)
January 2025
Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada. Electronic address:
Rad51 filaments are Rad51-coated single-stranded DNA and essential in homologous recombination (HR). The yeast Shu complex (Shu) is a conserved regulator of homologous recombination, working through its modulation on Rad51 filaments to direct HR-associated DNA damage response. However, the biochemical properties of Shu remain unclear, which hinders molecular insights into Shu's role in HR and the DNA damage response.
View Article and Find Full Text PDFNew Phytol
December 2024
Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000, Versailles, France.
Two recombinases, RAD51 and DMC1, catalyze meiotic break repair to ensure crossovers (COs) between homologous chromosomes (interhomolog) rather than between sisters (intersister). FIDGETIN-LIKE-1 (FIGL1) downregulates both recombinases. However, the understanding of how FIGL1 functions in meiotic repair remains limited.
View Article and Find Full Text PDFNucleic Acids Res
November 2024
Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
RAD54L is a DNA motor protein with multiple roles in homologous recombination DNA repair. In vitro, RAD54L was shown to also catalyze the reversal and restoration of model replication forks. In cells, however, little is known about how RAD54L may regulate the dynamics of DNA replication.
View Article and Find Full Text PDFNucleic Acids Res
November 2024
Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Replication-dependent DNA double-strand breaks are harmful lesions preferentially repaired by homologous recombination (HR), a process that requires processing of DNA ends to allow RAD51-mediated strand invasion. End resection and subsequent repair are two intertwined processes, but the mechanism underlying their execution is still poorly appreciated. The WRN helicase is one of the crucial factors for end resection and is instrumental in selecting the proper repair pathway.
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