The Bloom's Syndrome Helicase Interacts Directly with the Human DNA Mismatch Repair Protein hMSH6

Pedrazzi, Graziella; Bachrati, Csanád Z.; Selak, Nives; Studer, Ingrid; Petković, Maja; Hickson, Ian D.; Jiricny, Josef; Štagljar, Igor

doi:10.1515/bc.2003.128

Cited by 51 publications

(49 citation statements)

References 49 publications

(57 reference statements)

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“…In support of this idea, a physical interaction between Sgs1 and Msh6 proteins was reported using tandem affinity purification analysis (58), and BLM, a RecQ͞Sgs1P homolog, was shown to interact with human Msh6p both in vivo and in vitro (59). Alternatively, the Msh2p-Msh6p complex could bind to mismatches as they form in heteroduplex DNA and block further annealing.…”

Section: Discussionmentioning

confidence: 90%

Heteroduplex rejection during single-strand annealing requires Sgs1 helicase and mismatch repair proteins Msh2 and Msh6 but not Pms1

Sugawara

Goldfarb

Studamire

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

191

285

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Recombination between moderately divergent DNA sequences is impaired compared with identical sequences. In yeast, an HO endonuclease-induced double-strand break can be repaired by single-strand annealing (SSA) between flanking homologous sequences. A 3% sequence divergence between 205-bp sequences flanking the double-strand break caused a 6-fold reduction in repair compared with identical sequences. This reduction in heteroduplex rejection was suppressed in a mismatch repair-defective msh6⌬ strain and partially suppressed in an msh2 separation-offunction mutant. In mlh1⌬ strains, heteroduplex rejection was greater than in msh6⌬ strains but less than in wild type. Deleting PMS1, MLH2, or MLH3 had no effect on heteroduplex rejection, but a pms1⌬ mlh2⌬ mlh3⌬ triple mutant resembled mlh1⌬. However, correction of the mismatches within heteroduplex SSA intermediates required PMS1 and MLH1 to the same extent as MSH2 and MSH6. An SSA competition assay in which either diverged or identical repeats can be used for repair showed that heteroduplex DNA is likely to be unwound rather than degraded. This conclusion is supported by the finding that deleting the SGS1 helicase also suppressed heteroduplex rejection.G enetic recombination depends on the efficient and accurate search for homology between recipient and donor DNA substrates. Studies in both prokaryotes and eukaryotes have shown that mismatch repair proteins play a critical role in regulating this homology search during strand invasion (1, 2). A role for mismatch repair proteins in regulating recombination was first obtained in transformation studies performed in Pneumococcus. A small number of base-base differences between donor and recipient molecules significantly decreased the formation of stable transformants. This decrease, known as heteroduplex rejection, was suppressed by mutations in hexA and hexB, homologs of the Escherichia coli mismatch repair proteins MutS and MutL, respectively (3,4). The MutS and MutL proteins play key roles in the repair of base pair mismatches; MutS binds to mispairs and MutL appears to interact with MutS-mispair complexes to initiate downstream mismatch repair steps (5-8). Subsequent studies in bacteria, yeast, and humans showed that mismatch repair plays a critical role in repressing recombination between moderately divergent (homeologous) sequences (9-12).In Saccharomyces cerevisiae repair of mismatches arising during DNA replication or through heteroduplex DNA formation during recombination depends on the activity of several MutS and MutL homologs. Msh2p, Msh3p, Msh6p, and two MutL homologs, Mlh1p and Pms1p, have been shown to play major roles in mismatch repair, whereas two other MutL homologs, Mlh2p and Mlh3p, play specialized roles (13-19). These proteins appear to function as heterodimers in mismatch repair, because Msh2p-Msh3p, Msh2p-Msh6p, Mlh1p-Pms1p, Mlh1p-Mlh3p, and Mlh1p-Mlh2p complexes have been identified (20). Furthermore, the Msh2p-Msh6p complex shows a strong selectivity for base pair substitutions, whereas Msh2p-Ms...

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Section: Discussionmentioning

confidence: 90%

Heteroduplex rejection during single-strand annealing requires Sgs1 helicase and mismatch repair proteins Msh2 and Msh6 but not Pms1

Sugawara

Goldfarb

Studamire

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

191

285

View full text Add to dashboard Cite

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“…These data further implicate the involvement of hMSH2/6 in multiple cellular stress response pathways. Stagljar and coworkers have performed similar studies using HeLa cells and showed the BLM colocalization with MSH6, the reciprocal coimmunoprecipitation of BLM with MSH6, and the in vitro binding of the recombinant proteins (Pedrazzi et al, 2003). Lesion binding by p53 represents an important biological feature of this protein.…”

Section: Discussionmentioning

confidence: 90%

The mismatch DNA repair heterodimer, hMSH2/6, regulates BLM helicase

et al. 2004

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The human MSH2/6 complex is essential for mismatch recognition during the repair of replication errors. Although mismatch repair components have been implicated in DNA homologous recombination repair, the exact function of hMSH2/6 in this pathway is unclear. Here, we show that the recombinant hMSH2/6 protein complex stimulated the ability of the Bloom's syndrome gene product, BLM, to process Holliday junctions in vitro, an activity that could also be regulated by p53. Consistent with these observations, hMSH6 colocalized with BLM and phospho-ser15-p53 in hydroxyurea-induced RAD51 nuclear foci that may correspond to the sites of presumed stalled DNA replication forks and more likely the resultant DNA double-stranded breaks. In addition, we show that hMSH2 and hMSH6 coimmunoprecipitated with BLM, p53, and RAD51. Both the number of RAD51 foci and the amount of the BLM-p53-RAD51 complex are increased in hMSH2-or hMSH6-deficient cells. These data suggest that hMSH2/6 formed a complex with BLM-p53-RAD51 in response to the damaged DNA forks during double-stranded break repair.

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“…This assay was performed essentially as described previously (Wu et al, 2000;Pedrazzi et al, 2003). Briefly, 6 pmol of fulllength WRN, truncated WRN proteins (LGS-WRN, WRN P1 and WRN P2), and control protein UvrD were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose filters.…”

Section: Far-western Analysismentioning

confidence: 99%

The Werner syndrome protein is required for recruitment of chromatin assembly factor 1 following DNA damage

et al. 2006

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The Werner syndrome protein (WRN) and chromatin assembly factor 1 (CAF-1) are both involved in the maintenance of genome stability. In response to DNAdamaging signals, both of these proteins relocate to sites where DNA synthesis occurs. However, the interaction between WRN and CAF-1 has not yet been investigated. In this report, we show that WRN interacts physically with the largest subunit of CAF-1, hp150, in vitro and in vivo. Although hp150 does not alter WRN catalytic activities in vitro, and the chromatin assembly activity of CAF-1 is not affected in the absence of WRN in vivo, this interaction may have an important role during the cellular response to DNA replication fork blockage and/or DNA damage signals. In hp150 RNA-mediated interference (RNAi) knockdown cells, WRN partially formed foci following hydroxyurea (HU) treatment. However, in the absence of WRN, hp150 did not relocate to form foci following exposure to HU and ultraviolet light. Thus, our results demonstrate that WRN responds to DNA damage before CAF-1 and suggest that WRN may recruit CAF-1, via interaction with hp150, to DNA damage sites during DNA synthesis.

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The Bloom's Syndrome Helicase Interacts Directly with the Human DNA Mismatch Repair Protein hMSH6

Cited by 51 publications

References 49 publications

Heteroduplex rejection during single-strand annealing requires Sgs1 helicase and mismatch repair proteins Msh2 and Msh6 but not Pms1

Heteroduplex rejection during single-strand annealing requires Sgs1 helicase and mismatch repair proteins Msh2 and Msh6 but not Pms1

The mismatch DNA repair heterodimer, hMSH2/6, regulates BLM helicase

The Werner syndrome protein is required for recruitment of chromatin assembly factor 1 following DNA damage

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