The coding sequences of multiple human tumor suppressor genes include microsatellite sequences that are prone to mutations. Saccharomyces cerevisiae strains deficient in DNA mismatch repair (MMR) can be used to determine de novo mutation rates of these human tumor suppressor genes as well as any other gene sequence. Microsatellites in human TGFBR2, PTEN and APC genes were placed in yeast vector...

In yeast, DNA breaks are usually repaired by homologous recombination (HR). An early step for HR pathways is formation of a heteroduplex, in which a single-strand from the broken DNA molecule pairs with a strand derived from an intact DNA molecule. If the two strands of DNA are not identical, there will be mismatches within the heteroduplex DNA (hetDNA). In wild-type strains, these mismatches a...

HNPCC (Hereditary non-polyposis colorectal cancers) development is caused by mutation of genes included in system of mismatch repair genes. The mutation exists at 60% of patients in hMSH2 gene, 30% in hMLH1 and 10% both in hPMS1and hPMS2 genes. RER+ exists in about 90% in hereditary non-polyposis colorectal cancer and about 15-28% in sporadic cancers. The purpose of the study was to determine h...

Homeologous recombination between divergent DNA sequences is inhibited by DNA mismatch repair. In Escherichia coli, MutS and MutL respond to DNA mismatches within recombination intermediates and prevent strand exchange via an unknown mechanism. Here, using purified proteins and DNA substrates, we find that in addition to mismatches within the heteroduplex region, secondary structures within the...

OBJECTIVE Compare the processing of music-syntactic irregularities and physical oddballs between cochlear implant (CI) users and matched controls. METHODS Musical chord sequences were presented, some of which contained functionally irregular chords, or a chord with an instrumental timbre that deviated from the standard timbre. RESULTS In both controls and CI users, functionally irregular ch...

Recent work suggests that the eukaryotic system responsible for repairing DNA mismatches, and so correcting replication errors, is more complex than was thought; its multiple components have many cellular functions.

The overexpression of microRNA-21 (miR-21) is linked to a number of human tumors including colorectal cancer, where it appears to regulate the expression of tumor suppressor genes including p21, phosphatase and tensin homolog, TGFβ receptor II, and B-cell leukemia/lymphoma 2 -associated X protein. Here we demonstrate that miR-21 targets and down-regulates the core mismatch repair (MMR) recognit...

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome characterized by early age of onset colorectal cancer(mean45 years)as well as endometrial,urinarytract,and upper gastrointestinal adenocarcinomas. The HNPCC phenotype has been shown to segregate with germline mutations in the human homologues of the DNA mismatch repair genes MSH2, MLHJ, PMSJ, and PMS2. Ho...

Gene conversion, non-reciprocal transfer from one homologous sequence to another, is a major force in evolutionary dynamics, promoting co-evolution in gene families and maintaining similarities between repeated genes. However, the properties of the transfer - where it initiates, how far it proceeds and how the resulting conversion tracts are affected by mismatch repair - are not well understood...