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PubMed2006

Expression of DNA mismatch repair gene MSH2 in cytological material from lung cancer patients.

Mismatch repair genes encode for proteins responsible for the correction of bases incorrectly paired in the DNA. Loss of DNA mismatch repair activity has been associated with various cancers including tumors of the lung. In the present study, we have analyzed by immunocytochemistry the expression of MSH2 DNA repair gene in cytological material obtained by fine needle aspiration from a panel of 42 primary lung cancer patients. Specimens included 13 adenocarcinomas, 11 small cell carcinomas and 18 squamous cell carcinomas. Loss of expression or low expression was detected in 6 out of 13 (46%) adenocarcinomas and in 7 out of 18 (39%) of squamous cell carcinomas, although all 11 small cell carcinomas expressed MSH2. Our results suggest that loss of MSH2 expression is frequent in nonsmall cell carcinomas of the lung (P < 0.01, chi2 test). Evaluation of MSH2 expression can be applied for the screening of cytological material from fine needle aspirations from the lung.

Adenocarcinoma↗
PubMed2001

Eight novel germline MLH1 and MSH2 mutations in hereditary non-polyposis colorectal cancer families from Spain.

Germline mutations in the MLH1 and MSH2 genes, account for the majority of HNPCC families. We have screened such families from Spain by using DGGE analysis and subsequent direct sequencing techniques. In eight families we identified six novel MLH1 and two novel MSH2 mutations comprising one frame shift mutation (c.1420 del C), two missense mutations (L622H and R687W), two splice site mutations (c.1990-1 G>A and c.453+2 T>C and one nonsense mutation (K329X) in the MLH1 gene as well as two frame shift mutations (c.1979-1980 del AT and c.1704-1705 del AG) in the MSH2 gene. Our analysis contributes to the further characterization of the mutational spectrum of MLH1 and MSH2 genes in HNPCC families.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Seven novel MLH1 and MSH2 germline mutations in hereditary nonpolyposis colorectal cancer.

Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent hereditary form of colorectal cancer and is caused by germline mutations in mismatch repair (MMR) genes. The majority of mutations occur in MLH1 and MSH2. We report hereby seven novel germline mutations in these two genes (five in MLH1 and two in MSH2). All mutations have been found in families fulfilling criteria of the Bethesda guidelines and four of which also fulfilled the Amsterdam criteria. We identified three insertions or deletions of 1 bp leading to premature stop codons (MLH1: c.341delC, c.1413-1414insA; MSH2: c.1119delG) and three nonsense mutations (MLH1: c.67G>T [E23X], c.436C>T [Q146X]; MSH2: c.1857T>G [Y619X]). The corresponding tumors showed a high level of microsatellite instability (MSI-H) and a complete loss of expression of the affected protein. In addition, a missense mutation in MLH1 was identified (c.1984A>C [T662P]). The respective tumor also showed a high level of microsatellite instability but a reduced, rather then lost, expression of the MLH1-protein. This missense mutation was not found in 107 healthy control individuals and in 54 HNPCC patients.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Identification and characterization of genomic rearrangements of MSH2 and MLH1 in Lynch syndrome (HNPCC) by novel techniques.

It has recently been suggested that large genomic rearrangements account for 10-20% of all MSH2 mutations, and a lower proportion of all MLH1 mutations, among individuals with Lynch syndrome (hereditary non-polyposis colorectal cancer, HNPCC). These rearrangements are notoriously difficult to detect; moreover, for clinical purposes, simple tests must be devised to screen family members at risk. Here we used the multiplex ligation-dependent probe amplification (MLPA) method to screen for MSH2 and MLH1 deletions in 70 patients whose colorectal or endometrial tumors were MSI positive, yet no mutation had been found by genomic exon-by-exon sequencing of MSH2, MLH1, and MSH6. We identified five candidates with four different MSH2 deletions (exons 1-2, exons 1-6, exons 1-7 and exon 8) and one candidate with an MLH1 deletion (exons 3-6). To confirm the screening results and to characterize the breakpoints of these genomic deletions precisely, we used diploid-to-haploid conversion and inverse PCR as well as long-range PCR. In each case, we were able to pinpoint the breakpoint and design a simple diagnostic PCR. The procedures we used appear to be sensitive, specific, and simple enough for clinical use.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Ten novel MSH2 and MLH1 germline mutations in families with HNPCC.

Hereditary nonpolyposis colorectal cancer (HNPCC) is one of the most common hereditary cancer-susceptibility syndromes. Germline mutations in mismatch repair genes are associated with the clinical phenotype of HNPCC. We report ten novel germline mutations, three in MSH2 and seven in MLH1. All but one mutation have been found in families fulfilling criteria of the Bethesda guidelines; four of them additionally fulfilled the Amsterdam criteria I or II. Eight mutations were considered pathogenic and predictive diagnostics in healthy family members at risk shall be undertaken; these include five frameshift mutations leading to premature stop codons, in MSH2: c.1672delT (p.S558Xfs) and c.2466_2467delTG (p.C822X) and in MLH1: c.1023delG (p.R341Xfs), c.1127_1128dupAT (p.K377Xfs) and c.1310delC (p.P437Xfs); three mutations leading to splice aberrations, in MSH2: c.1661G>C (r.1511_1661del) and in MLH1: c.677+3A>C (r.589_677del) and c.1990-2A>G predicted to result in a splice site defect. The remaining two mutations are unclassified variants with assumed pathogenicity: one missense mutation in the highly conserved ATPase domain of MLH1 (c.122A>G [p.D41G]) and one in-frame insertion of twelve nucleotides in MLH1 (c.2155_2156insATGTGTTCCACA [p.I719delinsNVFHI]). These two mutations were not found in 102 alleles of healthy control individuals. The corresponding tumors from all patients showed a high level of microsatellite instability (MSI-H). Immunohistochemistry (IHC) revealed complete loss of expression of the affected protein in the tumor cells from all but three patients. The tumors from the patients with the mutations c.1127_1128dupAT and c.1990-2A>G showed a reduction of expression of the MLH1-protein, rather than complete loss. In the tumor from the patient with the missense mutation c.122A>G [p.D41G] a normal expression of the proteins coded by MLH1 and MSH2 was noticed.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Hereditary nonpolyposis colorectal cancer: frequent occurrence of large genomic deletions in MSH2 and MLH1 genes.

Hereditary nonpolyposis colorectal cancer (HNPCC) is often caused by a deficiency in DNA mismatch repair. By using conventional methods of mutation analysis, point mutations in the DNA mismatch repair genes MSH2 and MLH1 have been detected in up to 64% of patients suspected of HNPCC. However, large genomic deletions cannot be detected by these methods. In our study, we applied a semiquantitative multiplex PCR to detect the proportion of large deletions in patients meeting the Bethesda criteria whose tumours exhibited microsatellite instability (MSI). Of 368 unrelated patients, 180 exhibited MSI. In these patients, 68 disease-causing point mutations (38%) had previously been detected in the MSH2 and MLH1 genes by SSCP, heteroduplex analysis or DHPLC followed by direct sequencing. The remaining 112 patients (including 24 patients with rare missense or other unclarified variants) were examined for large deletions. We identified deletions in 19 patients (10.6%); 11/19 (58%) deletions were located in MSH2 and 8/19 (42%) in MLH1, respectively. The size of deletions ranged from 1 exon to a deletion of a whole gene. Five breakpoints of deletions were sequenced; Alu-repetitive elements were involved in all of them. In patients meeting the Amsterdam criteria the proportion of large deletions was 12.6%. A similar proportion of deletions was found in the group of patients with a positive family history for colorectal cancer and MSI tumours, not meeting the Amsterdam criteria. The results of our study suggest that large genomic deletions in both MSH2 and MLH1 genes play a considerable role in the pathogenesis of HNPCC and should be part of the routine HNPCC mutation detection protocols.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Histologic comparison of hereditary nonpolyposis colorectal cancer associated with MSH2 and MLH1 and colorectal cancer from the general population.

PURPOSE: Hereditary nonpolyposis colorectal cancer is reported to have special histologic features. This study compares the histologic features of hereditary nonpolyposis colorectal cancer to colorectal cancers from the general population when hereditary nonpolyposis colorectal cancer cases are restricted to families with known MSH2 and MLH1 mutations. METHODS: Thirty-seven cancers from kindreds carrying MSH2 mutations, 27 cancers from kindreds carrying MLH1 mutations, and 37 colorectal cancers from the general population were reviewed by a pathologist blinded to hereditary nonpolyposis colorectal cancer gene status. Tumor grade, growth pattern, Crohn's-like lymphoid reaction, mucin production, extent of disease in the bowel wall, and lymph node status were evaluated. RESULTS: Poor differentiation and Crohn's-like reaction were a feature of 44 and 49 percent of hereditary nonpolyposis colorectal cancer compared with 14 percent (P = 0.002) and 27 percent (P = 0.049) of colorectal cancers from the general population, respectively. There was no difference in growth pattern, mucin production, lymph node involvement, or local extent of disease between hereditary nonpolyposis colorectal cancer and colorectal cancers from the general population. Poor differentiation and lymph node metastases were found in 57 and 49 percent of MSH2 compared with 26 percent (P = 0.002) and 10 percent (P = 0.03) of MLH1-associated cancers, respectively. There was no difference in growth pattern, mucin production, Crohn's-like lymphoid reaction, or local extent of disease between subgroups of hereditary nonpolyposis colorectal cancer. CONCLUSIONS: Poor differentiation and Crohn's-like reaction are more common in hereditary nonpolyposis colorectal cancer than colorectal cancers from general population. Poor differentiation and lymph node metastases are more commonly seen in MSH2-associated cancers than MLH1. Evaluation of the natural history, pathogenesis, and prognosis of colorectal cancer in hereditary nonpolyposis colorectal cancer should include consideration of which mismatch repair genes are mutated and what the specific mutations are.

Adaptor Proteins, Signal Transducing↗
PubMed2005

The mutation spectrum of purified AID is similar to the mutability index in Ramos cells and in ung(-/-)msh2(-/-) mice.

Somatic hypermutation and class switch recombination are initiated by the enzyme activation-induced cytidine deaminase (AID). Although other models exist for AID function, one model suggests that AID initiates these processes by deaminating cytidines within DNA, thereby initiating mutagenic repair pathways that involve either UNG or Msh2. Recent work shows that GST-hAID prefers to mutate WRC motifs, a motif frequently mutated in vivo. Because this is a strong argument in favor of the DNA deamination model, we sought to extend this analysis by examining the activity of purified AID with a small polyhistidine tag (His-hAID) on all 16 trinucleotide combinations (i.e., NNC). Here we show that purified His-hAID preferentially mutated cytidines within WRC (i.e., A/T, A/G, C) motifs, but poorly mutated cytidines within GYC (G, C/T, C) motifs. We next compared this mutability preference with those in hypermutating Ramos cells and in msh2(-/-)ung(-/-) mice, since both are reduced or deficient in UNG- and/or Msh2-induced mutations and are thus likely to reflect the sequence specificity of the mutator in vivo. Indeed, the mutation spectrums of purified His-hAID and GST-hAID matched the trinucleotide mutability indexes in Ramos cells and in msh2(-/-)ung(-/-) mice. Thus, the activity of AID on single-stranded DNA produces the same mutation pattern as double-stranded DNA in hypermutating cells. These data lend support to the DNA deamination model and indicate that AID does not require co-factors for its WRC specificity.

Animals↗
PubMed1998

Schizosaccharomyces pombe exo1 is involved in the same mismatch repair pathway as msh2 and pms1.

Besides the MutLS-like system, Schizosaccharomyces pombe has an additional pathway of mismatch repair. This minor pathway, producing short excision tracts, repairs C/C and, with lower efficiency, other mismatches also. We investigated the involvement of the exo1+, msh2+ and pms1+ genes in the two pathways. The exo1+ gene encodes a 5' to 3' exonuclease, while msh2+ and pms1+ are homologs of Escherichia coli mutS and mutL, respectively. Intragenic two-factor crosses showed that exo1+, msh2+ and pms1+ are involved in the major, but not in the C/C-correcting, pathway. Post-meiotic segregation frequencies and mitotic mutation rates in single and double mutants supported this finding. Furthermore, msh2 delta was epistatic over exo1 delta, and the ExoI enzyme is likely to be redundant with other exonucleases.

Carrier Proteins↗
PubMed2005

Double frameshift mutations in APC and MSH2 in the same individual.

Heterozygous germline DNA mismatch repair gene mutations are typically associated with HNPCC. Here we report the case of a proband whose father was known for familial adenomatous polyposis. The number of polyps (less than ten) was not typical of polyposis; therefore, the diagnosis of HNPCC was entertained. Microsatellite instability analyses were performed on peripheral blood and biopsy of a right-sided dysplastic adenoma. The tumour tissue showed high-grade instability, and subsequently, immunohistochemistry showed that neither MSH2 nor MSH6 proteins were expressed in tumour cells. Prophylactic colectomy was performed, and an adenocarcinoma developing within the adenoma was diagnosed (pT1N0). Genomic DNA analysis revealed a novel mutation in MSH2 as a frameshift mutation in exon 7 (c.1,191_1,192dupG). Both parents of the proband were analyzed for MSH2 and APC mutations, and in the father, a truncating mutation in exon 15 of APC was identified as del3471-3473GAGA. This mutation was found to be present in the proband. His mother was found to bear the MSH2 exon 7 mutation. At follow-up, the proband was diagnosed with fundic, antral and duodenal adenomas (one fundic adenoma showed low-grade dysplasia). Several tubular rectal adenomas with low-grade dysplasia were excised. The patient later developed an intra-abdominal desmoid tumour.

Adenomatous Polyposis Coli↗
PubMed2006

Double frameshift mutations in APC and MSH2 in the same individual.

Heterozygous germline DNA mismatch repair gene mutations are typically associated with HNPCC. Here we report the case of a proband whose father was known for familial adenomatous polyposis. The number of polyps (less than ten) was not typical of polyposis; therefore, the diagnosis of HNPCC was entertained. Microsatellite instability analyses were performed on peripheral blood and biopsy of a right-sided dysplastic adenoma. The tumor tissue showed high-grade instability, and a subsequent, immunohistochemistry showed that neither MSH2 nor MSH6 proteins were expressed in tumor cells. Prophylactic colectomy was performed, and an adenocarcinoma developing within the adenoma was diagnosed (pT1N0). Genomic DNA analysis revealed a novel mutation in MSH2 as a frameshift mutation in exon 7 (c.1191_1192dupG). Both parents of the proband were analysed for MSH2 and APC mutations, and in the father, a truncating mutation in exon 15 of APC was identified as del3471-3473GAGA. This mutation was found to be present in the proband. His mother was found to bear the MSH2 exon 7 mutation. At the follow-up, the proband was diagnosed with fundic, antral and duodenal adenomas (one fundic adenoma showed low-grade dysplasia). Several tubular rectal adenomas with low-grade dysplasia were excised. The patient later developed an intra-abdominal desmoid tumor.

Adenomatous Polyposis Coli↗
PubMed2005

Aberrant splicing in MLH1 and MSH2 due to exonic and intronic variants.

Single base substitutions in DNA mismatch repair genes which are predicted to lead either to missense or silent mutations, or to intronic variants outside the highly conserved splicing region are often found in hereditary nonpolyposis colorectal cancer (HNPCC) families. In order to use the variants for predictive testing in persons at risk, their pathogenicity has to be evaluated. There is growing evidence that some substitutions have a detrimental influence on splicing. We examined 19 unclassified variants (UVs) detected in MSH2 or MLH1 genes in patients suspected of HNPCC for expression at RNA level. We demonstrate that 10 of the 19 UVs analyzed affect splicing. For example, the substitution MLH1,c.2103G > C in the last position of exon 18 does not result in a missense mutation as theoretically predicted (p.Gln701His), but leads to a complete loss of exon 18. The substitution MLH1,c.1038G > C (predicted effect p.Gln346His) leads to complete inactivation of the mutant allele by skipping of exons 10 and 11, and by activation of a cryptic intronic splice site. Similarly, the intronic variant MLH1,c.306+2dupT results in loss of exon 3 and a frameshift mutation due to a new splice donor site 5 bp upstream. Furthermore, we confirmed complete exon skipping for the mutations MLH1,c.1731G > A and MLH1,c.677G > A. Partial exon skipping was demonstrated for the mutations MSH2,c.1275A > G, MLH1,c.588+5G > A, MLH1,c.790+4A > G and MLH1,c.1984A > C. In contrast, five missense mutations (MSH2,c.4G > A, MSH2,c.2123T > A, MLH1,c.464T > G, MLH1,c.875T > C and MLH1,c.2210A > T) were found in similar proportions in the mRNA as in the genomic DNA. We conclude that the mRNA examination should precede functional tests at protein level.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Characterization of MLH1 and MSH2 alternative splicing and its relevance to molecular testing of colorectal cancer susceptibility.

The phenomenon of alternative splicing in the DNA mismatch repair genes MLH1 and MSH2 was extensively investigated by coupled reverse transcription-polymerase chain reaction in different human tissues, including 42 mononuclear blood cell samples--31 obtained from familial colon cancer patients or their at-risk relatives and 11 from healthy blood donors--7 normal colonic mucosae, 4 established human cancer cell lines, 8 colorectal tumors, and one sample each of ileum, liver, muscle, thymus, breast, and EBV-transformed lymphoblasts. Several isoforms were observed for each gene. Products of MLH1 alternative splicing included mRNAs lacking alternative exons 6/9, 9, 9/10, 9/10/11, 10/11, 12, 16, and 17. For MSH2, products lacking exons 5, 13, 2 through 7, and 2 through 8 were identified. The levels of expression were found to vary among different samples. All isoforms were found in a relevant fraction (43-100%) of the mononuclear blood cell samples, as well as in other tissues. The splicing variants were also detected in normal colonic mucosa, with the exceptions of the MLH1 -6/9 and -10/11 and the MSH2 -13 isoforms. Germline mutations of MLH1 and MSH2 confer constitutional predisposition to the development of colorectal cancer and other neoplasms. A substantial proportion of the mutations identified so far involve alterations of the normal splicing process. Knowledge of the existence of multiple alternative splicing events, not caused by genomic DNA changes, is important for the evaluation of the results of molecular diagnostic tests based on RNA analysis.

Adaptor Proteins, Signal Transducing↗
PubMed2007

A missense germline mutation in exon 7 of the MSH2 gene in a HNPCC family from center-Italy.

INTRODUCTION: Hereditary Non-Polyposis Colorectal Cancer (HNPCC) is an autosomal dominant inherited disease predisposing to the development of colorectal cancers and several other malignancies (endometrium, ovaries, stomach, small bowel, hepatobiliary and urinary tract). HNPCC is caused by germline mutations in any of the MisMatch Repair (MMR) genes. Mutations in MLH1 and MSH2 account for almost 90% of all identified ones. About 15% of mutations identified in MSH2 are missense ones. PATIENTS AND METHODS: We studied one family, fulfilling Amsterdam II criteria, referred to our Center for genetic counselling. The proband, and some of her relatives, have been investigated for microsatellite instability (MSI), immunohistochemical MMR protein staining and by direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). RESULTS: All patients carried the same novel MSH2 germline missense mutation (R359S) in exon 7, which determines the substitution of an Arginine, which is a basic amino acid, with a polar Serine residue (R359S). The mutation was associated with lack of expression of MSH2 protein and high microsatellite instability in tumour tissues. The same mutation has been detected in one healthy relative. CONCLUSIONS: The mutation here reported shows a high correlation with phenotype. The mutation is located in an evolutionary conserved domain. Taken together, our findings suggest evidence that the amino acid substitution can be interpreted as pathogenetic.

Adenocarcinoma↗
PubMed1995

A germline substitution in the human MSH2 gene is associated with high-grade dysplasia and cancer in ulcerative colitis.

BACKGROUND & AIMS: The DNA mismatch repair gene human MSH2 shows a germline mutation in certain family members with hereditary nonpolyposis colorectal cancer. There is an increased risk of colorectal cancer in patients with ulcerative colitis (UC) with extensive disease of > 8 years' duration; however, specific constitutional predisposing genetic abnormalities have not yet been identified. METHODS: A germline human MSH2 abnormality was sought in patients with UC with high-grade dysplasia or carcinoma. RESULTS: After direct sequencing of exon 13 and flanking regions of human MSH2, a germline T to C substitution was shown at the -6 intronic splice acceptor site of exon 13. This substitution was found in 14 of 53 patients with UC with high-grade dysplasia or carcinoma (26%) compared with 4 of 36 high-risk patients with UC without dysplasia or cancer (11%) (P < or = 0.04) and in 7 of 80 healthy adult blood donors (9%) (P < or = 0.003). The patients with UC who had the substitution were three times more likely to develop neoplasia than patients with UC who did not carry it. CONCLUSIONS: An intronic splice-site substitution in the human MSH2 gene is present in the general population but may predispose to cancer in the setting of UC.

Adult↗
PubMed2005

Genomic rearrangements in MSH2 and MLH1 are rare mutational events in Spanish patients with hereditary nonpolyposis colorectal cancer.

Colorectal cancer (CRC) is one of the most common neoplasms and a leading cause of death related to cancer worldwide. Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent autosomal dominant predisposition to the development of CRC, accounting for approximately 2.5% of the total CRC burden in Spain. Genomic rearrangements in the MSH2 and MLH1 genes have been reported to account for an important proportion of the mutation spectrum in HNPCC, and DNA dosage techniques have been developed facilitating molecular screening of such deletions/duplications. We screened for MSH2 and MLH1 genomic rearrangements by multiplex ligation-dependent probe amplification (MLPA) in 142 Spanish patients at risk for HNPCC prior to the exon-by-exon mutation scanning and found a deletion encompassing exons 9-16 of MSH2 and a duplication encompassing exons 11-16 of MSH2, both only in one case. These results showed that MSH2/MLH1 rearrangements in Spanish patients at risk for HNPCC seem to be a less frequent mutational event than in other populations.

Adaptor Proteins, Signal Transducing↗
PubMed2006

New founding mutation in MSH2 associated with hereditary nonpolyposis colorectal cancer syndrome on the Island of Tenerife.

Lynch syndrome or hereditary nonpolyposis colorectal cancer (HNPCC) is a hereditary syndrome with genetic heterogeneity. The disease is caused by mutations or epigenetic silencing in DNA mismatch repair genes, MLH1, MSH2, MSH6, PMS2 and MLH3, although the vast majority of cases correspond to mutations of MLH1 and MSH2. We herein describe a nucleotide change, c.2063T>G in exon 13 of the MSH2 gene, present in families that fulfill the Amsterdam criteria for Lynch syndrome and originate from northern Tenerife (Canary Islands-Spain). This mutation is expected to result in a nonconservative amino acid change, M688R, at the ATPase domain of the MSH2 protein. We found five large families with this mutation, and about half the individuals heterozygous for M688R developed malignancies by the sixth decade of life. In many cases analyzed, their tumors revealed loss of the normal allele, being homozygous for M688R. There is an evidence of historical isolation for the population studied, which could have favored a considerable genetic drift. The presence of the same mutation and the disease associated-haplotype conservation in families not directly related can be probably the consequence of a bottleneck in the founding of this population (rather than a relatively recent founding of the mutation).

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed2004

Functional and physical interactions between ERCC1 and MSH2 complexes for resistance to cis-diamminedichloroplatinum(II) in mammalian cells.

Bulky DNA lesions are mainly repaired by nucleotide excision repair (NER), in which the interaction of ERCC1 with XPA protein recruits the ERCC1-XPF complex, which acts as a structure-specific endonuclease in the repair process. However, additional functions besides NER have been suggested for the ERCC1-XPF complex, because ERCC1- or XPF-deficient rodent cells are significantly more sensitive to DNA interstrand cross-linking (ICL) agents such as cis-diamminedichloroplatinum(II) (CDDP) than any other NER-deficient cells and because ERCC1-deficient mice suffer a more severe phenotype than XPA-deficient mice. By using RNA interference we show here that suppression of ERCC1 expression increases the sensitivity of xeroderma pigmentosum group A (XPA)-deficient human cells to CDDP but not to UV. This increased sensitivity to CDDP is observed in mouse cells defective in Xpa as well but not in cells defective both in Xpa and the mismatch repair gene Msh2. These data suggest that ERCC1 and MSH2 are involved co-operatively in CDDP resistance in mammalian cells. As a possible molecular basis, we show further a physical interaction between endogenous ERCC1 and MSH2 complexes in HeLa cell extracts. Using tagged ERCC1 in COS7 cells, the minimum region in ERCC1 necessary for the immuno-precipitation of MSH2 is turned out to be the carboxyl-terminal domain between the 184th and 260th amino acid, which is partly overlapping with the XPF-binding domain of ERCC1. This interaction may be important in additional functions of ERCC1-XPF including the repair of CDDP-induced DNA damage.

Animals↗