A mutation in the MSH6 subunit of the Saccharomyces cerevisiae MSH2-MSH6 complex disrupts mismatch recognition.
In yeast, MSH2 interacts with MSH6 to repair base pair mismatches and single nucleotide insertion/deletion mismatches and with MSH3 to recognize small loop insertion/deletion mismatches. We identified a msh6 mutation (msh6-F337A) that when overexpressed in wild type strains conferred a defect in both MSH2-MSH6- and MSH2-MSH3-dependent mismatch repair pathways. Genetic analysis suggested that this phenotype was due to msh6-F337A sequestering MSH2 and preventing it from interacting with MSH3 and MSH6. In UV cross-linking, filter binding, and gel retardation assays, the MSH2-msh6-F337A complex displayed a mismatch recognition defect. These observations, in conjunction with ATPase and dissociation rate analysis, suggested that MSH2-msh6-F337A formed an unproductive complex that was unable to stably bind to mismatch DNA.
Bowers
J
J
Section of Genetics and Development, Cornell University, Ithaca, New York 14853-2703, USA.
Sokolsky
T
T
Quach
T
T
Alani
E
E
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D020137:Base Pair Mismatch; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D051718:MutS Homolog 2 Protein; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C098790:MSH6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein