Mismatch repair factor MSH2-MSH3 binds and alters the conformation of branched DNA structures predicted to form during genetic recombination.
Genetic studies in Saccharomyces cerevisiae predict that the mismatch repair (MMR) factor MSH2-MSH3 binds and stabilizes branched recombination intermediates that form during single strand annealing and gene conversion. To test this model, we constructed a series of DNA substrates that are predicted to form during these recombination events. We show in an electrophoretic mobility shift assay that S. cerevisiae MSH2-MSH3 specifically binds branched DNA substrates containing 3' single-stranded DNA and that ATP stimulates its release from these substrates. Chemical footprinting analyses indicate that MSH2-MSH3 specifically binds at the double-strand/single-strand junction of branched substrates, alters its conformation and opens up the junction. Therefore, MSH2-MSH3 binding to its substrates creates a unique nucleoprotein structure that may signal downstream steps in repair that include interactions with MMR and nucleotide excision repair factors.
Surtees
Jennifer A
JA
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703, USA.
Alani
Eric
E
D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D004260:DNA Repair / Q000235:genetics*; D004271:DNA, Fungal / Q000737:chemistry* / Q000235:genetics; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D051718:MutS Homolog 2 Protein / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013379:Substrate Specificity
D004271:DNA, Fungal; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein