scholarly journals BRCA2 regulates DMC1-mediated recombination through the BRC repeats

2016 ◽  
Vol 113 (13) ◽  
pp. 3515-3520 ◽  
Author(s):  
Juan S. Martinez ◽  
Catharina von Nicolai ◽  
Taeho Kim ◽  
Åsa Ehlén ◽  
Alexander V. Mazin ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Spatial Organization ◽  
Strand Exchange ◽  
Molecule Formation ◽  
Brca2 Protein ◽  
Dna Strand Exchange ◽  
Functional Consequences ◽  
Strand Invasion ◽  
Dna Strand ◽  
Stimulation Of

In somatic cells, BRCA2 is needed for RAD51-mediated homologous recombination. The meiosis-specific DNA strand exchange protein, DMC1, promotes the formation of DNA strand invasion products (joint molecules) between homologous molecules in a fashion similar to RAD51. BRCA2 interacts directly with both human RAD51 and DMC1; in the case of RAD51, this interaction results in stimulation of RAD51-promoted DNA strand exchange. However, for DMC1, little is known regarding the basis and functional consequences of its interaction with BRCA2. Here we report that human DMC1 interacts directly with each of the BRC repeats of BRCA2, albeit most tightly with repeats 1–3 and 6–8. However, BRC1–3 bind with higher affinity to RAD51 than to DMC1, whereas BRC6–8 bind with higher affinity to DMC1, providing potential spatial organization to nascent filament formation. With the exception of BRC4, each BRC repeat stimulates joint molecule formation by DMC1. The basis for this stimulation is an enhancement of DMC1–ssDNA complex formation by the stimulatory BRC repeats. Lastly, we demonstrate that full-length BRCA2 protein stimulates DMC1-mediated DNA strand exchange between RPA–ssDNA complexes and duplex DNA, thus identifying BRCA2 as a mediator of DMC1 recombination function. Collectively, our results suggest unique and specialized functions for the BRC motifs of BRCA2 in promoting homologous recombination in meiotic and mitotic cells.

scholarly journals Stimulation of Dmc1-mediated DNA strand exchange by the human Rad54B protein

2006 ◽  
Vol 34 (16) ◽  
pp. 4429-4437 ◽  
Author(s):  
Naoyuki Sarai ◽  
Wataru Kagawa ◽  
Takashi Kinebuchi ◽  
Ako Kagawa ◽  
Kozo Tanaka ◽  
...  
Keyword(s):  
Strand Exchange ◽  
Dna Strand Exchange ◽  
Dna Strand ◽  
Stimulation Of

scholarly journals The homologous recombination machinery modulates the formation of RNA–DNA hybrids and associated chromosome instability

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Lamia Wahba ◽  
Steven K Gore ◽  
Douglas Koshland
Keyword(s):  
Homologous Recombination ◽  
Genome Instability ◽  
Chromosome Instability ◽  
Rna Degradation ◽  
Strand Exchange ◽  
Hybrid Formation ◽  
Dna Strand Exchange ◽  
Dna Strand ◽  
Yeast Mutants

Genome instability in yeast and mammals is caused by RNA–DNA hybrids that form as a result of defects in different aspects of RNA biogenesis. We report that in yeast mutants defective for transcription repression and RNA degradation, hybrid formation requires Rad51p and Rad52p. These proteins normally promote DNA–DNA strand exchange in homologous recombination. We suggest they also directly promote the DNA–RNA strand exchange necessary for hybrid formation since we observed accumulation of Rad51p at a model hybrid-forming locus. Furthermore, we provide evidence that Rad51p mediates hybridization of transcripts to homologous chromosomal loci distinct from their site of synthesis. This hybrid formation in trans amplifies the genome-destabilizing potential of RNA and broadens the exclusive co-transcriptional models that pervade the field. The deleterious hybrid-forming activity of Rad51p is counteracted by Srs2p, a known Rad51p antagonist. Thus Srs2p serves as a novel anti-hybrid mechanism in vivo.

scholarly journals Homologous Recombination in Real Time: DNA Strand Exchange by RecA

2008 ◽  
Vol 30 (4) ◽  
pp. 530-538 ◽  
Author(s):  
Thijn van der Heijden ◽  
Mauro Modesti ◽  
Susanne Hage ◽  
Roland Kanaar ◽  
Claire Wyman ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Real Time ◽  
Strand Exchange ◽  
Dna Strand Exchange ◽  
Dna Strand

scholarly journals Stimulation of DNA Strand Exchange by the Human TBPIP/Hop2-Mnd1 Complex

2006 ◽  
Vol 281 (9) ◽  
pp. 5575-5581 ◽  
Author(s):  
Rima Enomoto ◽  
Takashi Kinebuchi ◽  
Makoto Sato ◽  
Hideshi Yagi ◽  
Hitoshi Kurumizaka ◽  
...  
Keyword(s):  
Strand Exchange ◽  
Dna Strand Exchange ◽  
Dna Strand ◽  
Stimulation Of

scholarly journals Human Rad54 Protein Stimulates DNA Strand Exchange Activity of hRad51 Protein in the Presence of Ca2+

2004 ◽  
Vol 279 (50) ◽  
pp. 52042-52051 ◽  
Author(s):  
Olga M. Mazina ◽  
Alexander V. Mazin
Keyword(s):  
Homologous Recombination ◽  
Atp Hydrolysis ◽  
Specific Interaction ◽  
Strand Exchange ◽  
Rad51 Protein ◽  
Recombination Proteins ◽  
Dna Strand Exchange ◽  
Dna Strand ◽  
Exchange Activity

Rad51 and Rad54 proteins play a key role in homologous recombination in eukaryotes. Recently, we reported that Ca2+is requiredin vitrofor human Rad51 protein to form an active nucleoprotein filament that is important for the search of homologous DNA and for DNA strand exchange, two critical steps of homologous recombination. Here we find that Ca2+is also required for hRad54 protein to effectively stimulate DNA strand exchange activity of hRad51 protein. This finding identifies Ca2+as a universal cofactor of DNA strand exchange promoted by mammalian homologous recombination proteinsin vitro. We further investigated the hRad54-dependent stimulation of DNA strand exchange. The mechanism of stimulation appeared to include specific interaction of hRad54 protein with the hRad51 nucleoprotein filament. Our results show that hRad54 protein significantly stimulates homology-independent coaggregation of dsDNA with the filament, which represents an essential step of the search for homologous DNA. The results obtained indicate that hRad54 protein serves as a dsDNA gateway for the hRad51-ssDNA filament, promoting binding and an ATP hydrolysis-dependent translocation of dsDNA during the search for homologous sequences.

scholarly journals The crossover function of MutSγ is activated via Cdc7-dependent stabilization of Msh4

2018 ◽  
Author(s):  
Wei He ◽  
H.B.D. Prasada Rao ◽  
Shangming Tang ◽  
Nikhil Bhagwat ◽  
Dhananjaya S. Kulkarni ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Chromosome Segregation ◽  
Holliday Junctions ◽  
Strand Exchange ◽  
Crossing Over ◽  
Chromosome Synapsis ◽  
Meiotic Crossover ◽  
Dna Strand Exchange ◽  
Dna Strand ◽  
Fundamental Mechanism

SUMMARYThe MutSγ complex, Msh4-Msh5, binds DNA joint-molecule (JM) intermediates during homologous recombination to promote crossing over and accurate chromosome segregation at the first division of meiosis. MutSγ facilitates the formation and biased resolution of crossover-specific JM intermediates called double Holliday junctions. Here we show that these activities are governed by regulated proteasomal degradation. MutSγ is initially inactive for crossing over due to an N-terminal degron on Msh4 that renders it unstable. Activation of MutSγ requires the Dbf4-dependent kinase, Cdc7 (DDK), which directly phosphorylates and thereby neutralizes the Msh4 degron. Phosphorylated Msh4 is chromatin bound and requires DNA strand exchange and chromosome synapsis, implying that DDK specifically targets MutSγ that has already bound nascent JMs. Our study establishes regulated protein degradation as a fundamental mechanism underlying meiotic crossover control.

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