Yeast best characterized eukaryotic MMR system is that of yeast And four (MSH1-MSH6) MutS Saccharomyces cerevisiae (Saccharomyces cerevisiae), of the six, but I there Homologues (PMS1 and MLH1-MLH3) Mutl. MSH1 MSH2,; required for maintenance and repair of mitochondrial DNA It is necessary for MSH6, the stability of the nuclear DNA and MSH3, MSH5 involved in the process of meiotic recombination and MSH4. Based on amino acid homology weak activity antimutator associated and MutS protein, the yeastprotein corresponding to HSM3 has been suggested that it MutS homolog of seven. Recent studies have shown When you’re growing very slowly, it occurs in standard growth conditions, mutator phenotype of HSM3 share was not only will reveal the cell.Hsm3p did not participate in the repair of replication errors that were removed in the standard in this way That this is a regular protein MMR does not take into account here is MMR machinery,.

MSH1 is focused on yeast mitochondria by a mitochondrial targeting Loss of mitochondrial function and sequence msh1 occur very quickly Strain. MMR role of mitochondria-specific, according to the heterojunction Instability of poly (GT) tract, and MSH1/msh1 strain, showed an increase of the mutation frequency of mitochondrial DN. Is MSH1 Yeast protein MSH is the only functionally dependent on MutS of other family members,There is a possibility of the MutS protein display articles, prokaryotic its active form Is a homodimer. It has the mitochondrial function of MSH1 It may be the creation of family, the version primitive of this protein in the MutS Phylogenetic analysis of recent, to support this hypothesis and eukaryotes.

According to this model from postsymbiotic, primitive MSH1 gene Mitochondria are transmitted to the nucleus following the loss of copies of mitochondrial genes. In the course of evolution, gene duplication of primitive MSH1 You will be able reading, duplicate copies evolve a new function proteins of different MSH exist in eukaryotes today. Forecast MSH1-like protein is encoded in the genome of Arabidopsis thaliana, but Is such Homologs have been found in other organisms. It is interesting Mutl homolog not mitochondria have been identified in yeast. Genetic evidence suggests that the yeast MSH2 is required for mismatch Whereas the MSH6 and MSH3, correction of the nuclear DNA is involved in the repair Different subsets of mutations intermediate.

This model of Have been achieved by MutS of as two separate the mismatch recognition yeast MMR Heterodimer consisting of MSH2 and MSH6 or MSH3. Delete Indicates that the C-terminal region is important for interaction with MSH6, MSH2 analysis may be a mutation of the C-terminal helix-turn-helix motif I interfere with the interaction with MSH6. I have shown in vitro binding studies
MSH6 – MSH2 which can bind double-stranded DNA molecules having a base or a base Loop of or mismatch will only bind to double-stranded, including the insertion removal cycles On the other hand MSH2-MSH3. Both types of  The sequence context and the surrounding mismatch, is an important element  Mismatch binding specificity. In previous studies, we have shown the MSH2,
If any, it is possible alone, to bind the contradiction in vivo significance, it is not clear of this observation. In addition to the specific binding to double-stranded mismatch-containing  Bound DNA molecule of MSH6 complex – MSH2 Synthesis and MSH2  Holiday junction has been reported.

Yeast MSH2 it is built in, and complexes including the region  Specific directly, but it connects the mismatch not well defined
I will present in the MSH6 subunit MSH3 probably. UV cross-linking test  I shows the covalent attachment of components of MSH6 MSH6 – MSH2  Complex for mismatch DNA (25,114) supports this hypothesis. In addition, I will eliminate the in vitro binding inconsistent MSH2, MSH6 complex variant to be deduced amino acid that is sitedirected qualified, to be involved in DNA binding MSH6 (25). Complex of the three-way between MLH1, MSH2 or MSH2-MSH3 or and PMS1 – MSH6 mismatchbound is, and was observed in vitro in.  Hetero, including suspicion of MSH2, the conversation using one of the following three forms:  Heterodimer including MLH1 you begin any of the procedures in downstream defined future  Masu MMR.

It is a P-loop motif for binding triphosphate nucleoside I encourage half of the binding / hydrolysis of ATP and MutS of the C-terminus of the dissociation Step complex MutS-mismatch appears to be essential for downstream of MMR. Mutant retained ATP-binding domain of MutS of Cause is bound to eliminate irreversible discrepancy probably is associated with a dominant negative mutator phenotype in vivo Link a competent repair complex. As visualized by electron microscopy, Trigger, add the ATP of the formation of the complex MutS mismatch binding Mismatch between the structure and MutS at the base of the form loop loop Top. Modri ​​ch have proposed that this structure is generated From ATP hydrolysis according to the two-way transfer of MutS in Mismatch.

Was the crystal structure (W & P Xie Yang, personal communication), of each complex MutS dimer of T. Aqua (T Sixma, personal communication) and MutS dimer of Escherichia coli and oligonucleotides containing mismatches Has been resolved. Structure are very similar and provide insight protein invaluable Function. Although both of these proteins function as subunit homodimers, the monomeric I have different units. It is essential in the formation of the heterodimer subunits of the same structure of the protein, from an evolutionary perspective As he explained the reason for existence as a hetero only of eukaryotic MutS complex. Crystal structure shows that it has one of the MutS two grooves Represents the mismatch binding site, and includes the identification saved phenylalanine in the previous cross-linking study. The 1 subunit is actually

Both in the form of DNA clamp, binds the mismatch. The crystal structure confirms the helix-turn-helix domain that is highly conserved At the end, as shows, and is important for dimerization of it of MutS, the DNA-binding site and ATP-ase site is a complex site that uses domain Both subunits. According to the complex nature of the site break like this Dimerization, simultaneous loss helix-turn-helix domain result of ATP (WYang P and Xie, personal communication) bond mismatch and hydrolysis. Direction discrimination of signals in E. coli MMR system provided by Transition state of the non-methylated DNA newly synthesized.

In particular, it marks the strands broken to re-synthesis and exonuclease removal as this, Azimut protein cleaves the unmethylated strand of the hemi-site GATC Dam methylation. Mismatch of the dependent section and Chelsea, It is activated in vitro by a complex of MutS non DNA.Because and Mutl is, are stalling the exonuclease specific endonuclease activity, active UvrD of (Mutu) helicase, to unwind the molecule of double is required. Undoing in the UvrD helicase to start earning participants and in a direct way to the contradiction. Nature of methyl-oriented E. coli system, is an effective way to distinguish the daughter strand templates and DNA replication at the time of MMR, but this mechanism is universal in prokaryotes, (see below) eukaryotes It does not apply obviously. In the absence of active Muth, existing participant of one strand of the duplex is sufficient to duplex-specific repair in vitro.

Thing for MMR, however, genetic research is essential as opposed to Mutl has been shown MutS protein with Muth to determine was difficult its precise role in MMR. The N-terminal region of the protein family Mutl is well preserved, and is included Dimerization region ATP binding / hydrolysis area, of Mutl I seem to be present in the C-terminal region of the protein. The crystallographic studies, the ATP binding leads to dimerization of the N-terminus has been shown Part of the protein, as well as structural changes It was speculated that play an important role in adjusting the initial stage of mismatch recognition to downstream processing. The Mutl, that interact in this way is expected to MMR and multiple components.

It is shown using the analysis and affinity purification of Delete a direct interaction between the MutS with Mutl of the MutS C-terminal region is shown to be important for Mutl-MutS interaction . In addition MutS interaction Mutl-between, the direct interaction,
It is Mutl C-terminal region of Azimut and Mutl only has been proven To stimulate the Azimut of endonuclease activity has been shown. C-terminal Interacts with UvrD directly and Mutl area, participated in the activation Helicase activity of this protein. Mutl guess to load the UvrD In a direct way, because helicase participants, DNA development revenue Diverge. The overall pattern that emerges from the biochemical study Mutl coordinate mismatch binding activity of MutS it with Chelsea UvrD helicase activity and cutting, and therefore direct removal circuit process.

Mismatch repair (MMR) system is critical to maintaining the overall Integrity of the genetic material, and the main features of this system. It is stored in the course of a highly evolved. MMR system is well-known for his role best. Located on the lower level acceptable repair after replication of DNA polymerization errors is important in order to maintain the mutation. In addition to the recognition replicationgenerated mismatch, also MMR proteins, but it is only intended to correct the mismatch in the hetero.

Recombination intermediates. Mismatch recognition in recombinant intermediates can induce the repair process leading to genetic transformation the gene is found Can cause anti-recombinant activity to prevent recombination events to go to completion or event,. Anti-recombination activity of MMR. Protein promotes genomic stability by suppressing the reaction between the divergent Sequences from different organisms, or present in the genome of a single. In addition to recognition and processing of DNA mismatch, including Äúnormal, the AU, The base MMR system, I play a role in response to DNA damage. In the end, MMR eukaryotic proteins have, recombination of roles not related to non-compliance Protein and some identification, have evolved an important role in the metabolism meiotic chromosome. This assessment summarizes the different roles of MMR proteins. To promote genetic stability, we are focused on the impact of MMR of genetic defect.

The (MMR), 2 (PMS2) protein that is also known as PMS1 protein homolog 2, separation meiosis after increased the DNA mismatch repair. Members of PMS2 gene family has been found in a cluster of seven on chromosome. Protein of PMS2 96 kDa is PMS1, and MLH1, MLH3 mismatch repair closely related is the homolog of gene Mutl of bacteria. Coordinate bond This complex of other proteins, PMS2 protein heterodimers with proteins MLH1 that are activated in the presence of ATP to repair errors that occurred during cell preparation of DNA for cell division I will form a.

Loss of PMS2 expression in tumors, can determine the suitability for mutation analysis is useful in identifying a mutation carrier hMLH1. The defect account of PMS2 gene for a significant proportion of tumor microsatellite instability and, for a significant percentage of small but colon cancer. Dominant genetic disorder associated with changes in the HNPCC syndrome known as Turcot syndrome, hereditary colon cancer, nonpolyposis (HNPCC) is clearly too much, PMS2 is associated with.

Nonpolyposis, also known as Lynch syndrome (HNPCC) is an autosomal that the colon, uterus, stomach, as well as upper urinary tract, and predispose individuals to the development of other cancers also, colon cancer is hereditary is a dominantly inherited cancer syndrome. People with HNPCC / Lynch syndrome, have a germline mutation in one of several genes involved in DNA mismatch repair. Most of the mutations that are associated with the occurrence HNPCC / Lynch syndrome in the MLH1 and MSH2, but mutation of PMS2 and MSH6 have also been identified.

There are family history and / or personal, some strategies for individuals to evaluate a measure of HNPCC / Lynch syndrome cancer. Typically, the first step, the HNPCC / Lynch syndrome involving loss of protein expression of one or more and (the presence of a set of types changes repetitive DNA called microsatellites) Microsatellite instability genes associated with HNPCC / Lynch syndrome is to evaluate tumor characteristics common to people with.

Immunohistochemistry microsatellite instability and (MSI) (IHC), is interpreted together in order to assess the risk of HNPCC / Lynch syndrome generally. This suggests a defect DNA mismatch repair high level of MSI in the tumor, but this knowledge does not provide a gene information involved. Used to evaluate the protein PMS2 in HNPCC / Lynch expression of MLH1, and MSH2, MSH6,, test strategy, IHC is a cancer-related syndrome further. Loss of expression of one or more of these proteins in tumors, it will be useful to identify that it should be analyzed genes associated with mutations of interest (s). IHC and MSI are read together, but they also, separately in order to respond to the clinical situation in which barriers to be run these tests at the same time (for example, financial problems, requirements of the sample) and is present are available.

You can determine the loss or retention of PMS2 protein expression and MLH1, MSH2, MSH6 in IHC alone. When the protein all four are present as approximately 5% of the tumors that display MSI with normal expression of the four proteins these genes, potential HNPCC / Lynch syndrome is reduced but not eliminated. Loss of protein in one or more of IHC shows the probability of HNPCC / Lynch syndrome is increased and DNA mismatch repair of incomplete tumor. Germ cell test Each gene (s) (i.e., mutation analysis) it is possible for to identify germline mutations cause, is performed in order to enable testing of individuals predicted risk.