title: Bipartite stimulatory action of the Hop2-Mnd1 complex on the Rad51 recombinase.
abstract: The HOP2 and MND1 genes are indispensable for meiotic recombination. The products of these genes associate to form a stable heterodimeric complex that binds DNA and stimulates the recombinase activity of Rad51 and Dmc1. Here we conduct molecular studies to delineate the action mechanism of the Hop2-Mnd1 complex. We present evidence to implicate Hop2 as the major DNA-binding subunit and Mnd1 as the prominent Rad51 interaction entity. Hop2-Mnd1 stabilizes the Rad51-single-stranded DNA (ssDNA) nucleoprotein filament, the catalytic intermediate in recombination reactions. We also show that Hop2-Mnd1 enhances the ability of the Rad51-ssDNA nucleoprotein filament to capture duplex DNA, an obligatory step in the formation of the synaptic complex critical for DNA joint formation. Thus, our results unveil a bipartite mechanism of Hop2-Mnd1 in homologous DNA pairing: stabilization of the Rad51 presynaptic filament and duplex DNA capture to enhance synaptic complex formation.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Chi
authors.forename: Joseph
authors.initials: J
authors.lastname: San Filippo
authors.forename: Michael G
authors.initials: MG
authors.lastname: Sehorn
authors.forename: Galina V
authors.initials: GV
authors.lastname: Petukhova
authors.forename: Patrick
authors.initials: P
authors.lastname: Sung
mesh_terms: D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D023902:Chromosome Pairing; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008540:Meiosis; D051379:Mice; D008954:Models, Biological; D046912:Multiprotein Complexes; D051135:Rad51 Recombinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004277:DNA, Single-Stranded; C113830:HOP2 protein, S cerevisiae; C454441:MND1 protein, S cerevisiae; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C495153:RAD51 protein, human; D051135:Rad51 Recombinase