Similar Datasets
Project description:Genomic imprinting is controlled by CpG-rich regions (ICRs) acquiring differential methylation in the female and male germline and maintaining it in a parental origin-specific manner in somatic cells. Despite their expected mutation rate due to spontaneous deamination of methylated cytosines, ICRs maintain their CpG-richness and show conservation of CpG-bearing transcription binding sites in mammals. In order to gain further insights into the mechanisms of maintenance of methyl CpGs, we sought to identify the proteins interacting with the methylated allele of the ICRs, by determining the interactors of ZFP57 that recognizes a specific methylated ICR motif in mouse ESCs. Several proteins including factors involved in mRNA processing/splicing, chromatin organization, transcription and DNA repair were identified through a tagged approach coupled to LC–MS/MS analysis. The demonstration of the components of the post-replicative mismatch-repair (MMR) complex as ZFP57 interactors prompted us to investigate the DNA binding profile of MSH2 and MSH6 by chromatin immunoprecipitation and sequencing. We found that these proteins were enriched at the methylated allele of the ICRs and their binding was mediated by the ZFP57/KAP1 complex, suggesting that the MMR complex is recruited to these loci to preserve their genetic integrity.
2022-08-16 | GSE205042 | GEO
Project description:Genomic imprinting is controlled by CpG-rich regions (ICRs) acquiring differential methylation in the female and male germline and maintaining it in a parental origin-specific manner in somatic cells. Despite their expected mutation rate due to spontaneous deamination of methylated cytosines, ICRs maintain their CpG-richness and show conservation of CpG-bearing transcription binding sites in mammals. In order to gain further insights into the mechanisms of maintenance of methyl CpGs, we sought to identify the proteins interacting with the methylated allele of the ICRs, by determining the interactors of ZFP57 that recognizes a specific methylated ICR motif in mouse ESCs. Several proteins including factors involved in mRNA processing/splicing, chromatin organization, transcription and DNA repair were identified through a tagged approach coupled to LC–MS/MS analysis. The demonstration of the components of the post-replicative mismatch-repair (MMR) complex as ZFP57 interactors prompted us to investigate the DNA binding profile of MSH2 and MSH6 by chromatin immunoprecipitation and sequencing. We found that these proteins were enriched at the methylated allele of the ICRs and their binding was mediated by the ZFP57/KAP1 complex, suggesting that the MMR complex is recruited to these loci to preserve their genetic integrity.
2022-08-16 | GSE205041 | GEO
Project description:The mismatch-repair proteins MSH2 and MSH6 interact with the imprinting control regions through the ZFP57-KAP1 complex
| PRJNA843324 | ENA
Project description:The mismatch-repair proteins MSH2 and MSH6 interact with the imprinting control regions through the ZFP57-KAP1 complex (RRBS)
| PRJNA843326 | ENA
Project description:The mismatch-repair proteins MSH2 and MSH6 interact with the imprinting control regions through the ZFP57-KAP1 complex (ChIP-Seq)
| PRJNA843327 | ENA
Project description:The heterodimeric human MSH2-MSH6 protein initiates DNA mismatch repair (MMR) by recognizing mismatched bases that result from replication errors. Msh2(G674A) or Msh6(T1217D) mice that have mutations in or near the ATP binding site of MSH2 or ATP hydrolysis catalytic site of MSH6 develop cancer and have a reduced lifespan due to loss of the MMR pathway (Lin, D. P., Wang, Y., Scherer, S. J., Clark, A. B., Yang, K., Avdievich, E., Jin, B., Werling, U., Parris, T., Kurihara, N., Umar, A., Kucherlapati, R., Lipkin, M., Kunkel, T. A., and Edelmann, W. (2004) Cancer Res. 64, 517-522; Yang, G., Scherer, S. J., Shell, S. S., Yang, K., Kim, M., Lipkin, M., Kucherlapati, R., Kolodner, R. D., and Edelmann, W. (2004) Cancer Cell 6, 139-150). Mouse embryonic fibroblasts from these mice retain an apoptotic response to DNA damage. Mutant human MutSα proteins MSH2(G674A)-MSH6(wt) and MSH2(wt)-MSH6(T1219D) are profiled in a variety of functional assays and as expected fail to support MMR in vitro, although they retain mismatch recognition activity. Kinetic analyses of DNA binding and ATPase activities and examination of the excision step of MMR reveal that the two mutants differ in their underlying molecular defects. MSH2(wt)-MSH6(T1219D) fails to couple nucleotide binding and mismatch recognition, whereas MSH2(G674A)-MSH6(wt) has a partial defect in nucleotide binding. Nevertheless, both mutant proteins remain bound to the mismatch and fail to promote efficient excision thereby inhibiting MMR in vitro in a dominant manner. Implications of these findings for MMR and DNA damage signaling by MMR proteins are discussed.
| S-EPMC3323011 | biostudies-literature
Project description:DNA mismatch repair (MMR) is an important postreplication process that eliminates mispaired or unpaired nucleotides to ensure genomic replication fidelity. In humans, Msh2-Msh6 and Msh2-Msh3 are the two mismatch repair initiation factors that recognize DNA lesions. While X-ray crystal structures exist for these proteins in complex with DNA lesions, little is known about their structures during the initial search along nonspecific double-stranded DNA, because they are short-lived and difficult to determine experimentally. In this study, various computational approaches were used to sidestep these difficulties. All-atom and coarse-grained simulations based on the crystal structures of Msh2-Msh3 and Msh2-Msh6 showed no translation along the DNA, suggesting that the initial search conformation differs from the lesion-bound crystal structure. We modeled probable search-mode structures of MSH proteins and showed, using coarse-grained molecular dynamics simulations, that they can perform rotation-coupled diffusion on DNA, which is a suitable and efficient search mechanism for their function and one predicted earlier by fluorescence resonance energy transfer and fluorescence microscopy studies. This search mechanism is implemented by electrostatic interactions among the mismatch-binding domain (MBD), the clamp domains, and the DNA backbone. During simulations, their diffusion rate did not change significantly with an increasing salt concentration, which is consistent with observations from experimental studies. When the gap between their DNA-binding clamps was increased, Msh2-Msh3 diffused mostly via the clamp domains while Msh2-Msh6 still diffused using the MBD, reproducing the experimentally measured lower diffusion coefficient of Msh2-Msh6. Interestingly, Msh2-Msh3 was capable of dissociating from the DNA, whereas Msh2-Msh6 always diffused on the DNA duplex. This is consistent with the experimental observation that Msh2-Msh3, unlike Msh2-Msh6, can overcome obstacles such as nucleosomes. Our models provide a molecular picture of the different mismatch search mechanisms undertaken by Msh2-Msh6 and Msh2-Msh3, despite the similarity of their structures.
| S-EPMC7872316 | biostudies-literature
Project description:Previous analyses of both Thermus aquaticus MutS homodimer and Saccharomyces cerevisiae Msh2-Msh6 heterodimer have revealed that the subunits in these protein complexes bind and hydrolyze ATP asymmetrically, emulating their asymmetric DNA binding properties. In the MutS homodimer, one subunit (S1) binds ATP with high affinity and hydrolyzes it rapidly, while the other subunit (S2) binds ATP with lower affinity and hydrolyzes it at an apparently slower rate. Interaction of MutS with mismatched DNA results in suppression of ATP hydrolysis at S1-but which of these subunits, S1 or S2, makes specific contact with the mismatch (e.g., base stacking by a conserved phenylalanine residue) remains unknown. In order to answer this question and to clarify the links between the DNA binding and ATPase activities of each subunit in the dimer, we made mutations in the ATPase sites of Msh2 and Msh6 and assessed their impact on the activity of the Msh2-Msh6 heterodimer (in Msh2-Msh6, only Msh6 makes base specific contact with the mismatch). The key findings are: (a) Msh6 hydrolyzes ATP rapidly, and thus resembles the S1 subunit of the MutS homodimer, (b) Msh2 hydrolyzes ATP at a slower rate, and thus resembles the S2 subunit of MutS, (c) though itself an apparently weak ATPase, Msh2 has a strong influence on the ATPase activity of Msh6, (d) Msh6 binding to mismatched DNA results in suppression of rapid ATP hydrolysis, revealing a "cis" linkage between its mismatch recognition and ATPase activities, (e) the resultant Msh2-Msh6 complex, with both subunits in the ATP-bound state, exhibits altered interactions with the mismatch.
| S-EPMC4674293 | biostudies-literature
Project description:DNA mismatch repair (MMR) is a highly conserved mutation avoidance mechanism that corrects DNA polymerase misincorporation errors. In initial steps in MMR, Msh2-Msh6 binds mispairs and small insertion/deletion loops, and Msh2-Msh3 binds larger insertion/deletion loops. The msh2?1 mutation, which deletes the conserved DNA-binding domain I of Msh2, does not dramatically affect Msh2-Msh6-dependent repair. In contrast, msh2?1 mutants show strong defects in Msh2-Msh3 functions. Interestingly, several mutations identified in patients with hereditary non-polyposis colorectal cancer map to domain I of Msh2; none have been found in MSH3. To understand the role of Msh2 domain I in MMR, we examined the consequences of combining the msh2?1 mutation with mutations in two distinct regions of MSH6 and those that increase cellular mutational load (pol3-01 and rad27). These experiments reveal msh2?1-specific phenotypes in Msh2-Msh6 repair, with significant effects on mutation rates. In vitro assays demonstrate that msh2?1-Msh6 DNA binding is less specific for DNA mismatches and produces an altered footprint on a mismatch DNA substrate. Together, these results provide evidence that, in vivo, multiple factors insulate MMR from defects in domain I of Msh2 and provide insights into how mutations in Msh2 domain I may cause hereditary non-polyposis colorectal cancer.
| S-EPMC3163898 | biostudies-other
Project description:The observation that Cadmium (Cd(2+)) inhibits Msh2-Msh6, which is responsible for identifying base pair mismatches and other discrepancies in DNA, has led to the proposal that selective targeting of this protein and consequent suppression of DNA repair or apoptosis promote the carcinogenic effects of the heavy metal toxin. It has been suggested that Cd(2+) binding to specific sites on Msh2-Msh6 blocks its DNA binding and ATPase activities. To investigate the mechanism of inhibition, we measured Cd(2+) binding to Msh2-Msh6, directly and by monitoring changes in protein structure and enzymatic activity. Global fitting of the data to a multiligand binding model revealed that binding of about 100 Cd(2+) ions per Msh2-Msh6 results in its inactivation. This finding indicates that the inhibitory effect of Cd(2+) occurs via a nonspecific mechanism. Cd(2+) and Msh2-Msh6 interactions involve cysteine sulfhydryl groups, and the high Cd(2+):Msh2-Msh6 ratio implicates other ligands such as histidine, aspartate, glutamate, and the peptide backbone as well. Our study also shows that cadmium inactivates several unrelated enzymes similarly, consistent with a nonspecific mechanism of inhibition. Targeting of a variety of proteins, including Msh2-Msh6, in this generic manner would explain the marked broad-spectrum impact of Cd(2+) on biological processes. We propose that the presence of multiple nonspecific Cd(2+) binding sites on proteins and their propensity to change conformation on interaction with Cd(2+) are critical determinants of the susceptibility of corresponding biological systems to cadmium toxicity.
| S-EPMC4684310 | biostudies-literature