background: meiotic genes are very important candidates for genes contributing to female and male infertility. mammalian mutl homologues have dual roles in dna mismatch repair (mmr) after replication errors and meiotic reciprocal recombination. the mutl homologs, mlh1 and mlh3 , are crucial for meiotic reciprocal recombination and human fertility. in this study the functional polymorphisms of m...

background: hereditary non-polyposis colorectal cancer (hnpcc) is a common hereditary cancer predisposing syndrome has molecular and clinicopathological features still have remained ambiguous within iranian populations. we discuss in this article some molecular and clinicopathological features of the condition. methods: the study was a descriptive retrospective and designed on 1659 colorectal c...

background: germline mutations in mmr genes are reported to be present in more than 70% of hnpcc cases. but, there is a paucity of data regarding the importance of defect of mmr system in the gastric cancer in general. so, in this study, we used ihc stain formlh1,msh2, pms2 andmsh6 to reveal profile ofmmr expression in patients with gastric cancer. materials and methods: this study was performe...

Fragile X-associated disorders are Repeat Expansion Diseases that result from expansion of a CGG/CCG-repeat in the FMR1 gene. Contractions of the repeat tract also occur, albeit at lower frequency. However, these contractions can potentially modulate disease symptoms or generate an allele with repeat numbers in the normal range. Little is known about the expansion mechanism and even less about ...

Typically disease-causing CAG/CTG repeats expand, but rare affected families can display high levels of contraction of the expanded repeat amongst offspring. Understanding instability is important since arresting expansions or enhancing contractions could be clinically beneficial. The MutSβ mismatch repair complex is required for CAG/CTG expansions in mice and patients. Oddly, by unknown mechan...

RAD3 functions in DNA repair and transcription in Saccharomyces cerevisiae and particular rad3 alleles confer a mutator phenotype, possibly as a consequence of defective mismatch correction. We assessed the potential involvement of the Rad3 protein in mismatch correction by comparing heteroduplex repair in isogenic rad3-1 and wild-type strains. The rad3-1 allele increased the spontaneous mutati...

DNA-binding proteins search for specific targets via facilitated diffusion along a crowded genome. However, little is known about how crowded DNA modulates facilitated diffusion and target recognition. Here we use DNA curtains and single-molecule fluorescence imaging to investigate how Msh2-Msh3, a eukaryotic mismatch repair complex, navigates on crowded DNA. Msh2-Msh3 hops over nucleosomes and...

In most organisms, the mismatch repair (MMR) system plays an important role in substantially lowering mutation rates and blocking recombination between nonidentical sequences. In Saccharomyces cerevisiae, the products of three genes homologous to Escherichia coli mutS-MSH2, MSH3, and MSH6-function in MMR by recognizing mispaired bases. To determine the effect of MMR on single-base pair mismatch...

A quantitative genetic assay was developed to monitor alterations in tract lengths of trinucleotide repeat sequences in Saccharomyces cerevisiae. Insertion of (CAG)50 or (CTG)50 repeats into a promoter that drives expression of the reporter gene ADE8 results in loss of expression and white colony color. Contractions within the trinucleotide sequences to repeat lengths of 8 to 38 restore functio...