The Mgs1/WRNIP1 ATPase is required to prevent a recombination salvage pathway at damaged replication forks
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ABSTRACT:
PROVIDER: PRJNA594414 | ENA |
REPOSITORIES: ENA
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Project description:DNA damage tolerance (DDT) is crucial for genome integrity maintenance. DDT is mainly carried out by template switch recombination, an error-free mode of overcoming DNA lesions, or translesion DNA synthesis, which is error-prone. Here we investigated the role of Mgs1/WRNIP1 in modulating DDT. Using budding yeast, we found that elimination of Mgs1 in cells lacking Rad5, an essential protein for DDT, activates an alternative mode of DNA damage bypass, driven by recombination, that allows chromosome replication and cell viability under stress conditions that block DNA replication forks. This salvage pathway is RAD52- and RAD59-dependent, requires the DNA polymerase and PCNA-modification at K164, and is enabled by Esc2 and the PCNA-unloader Elg1, being inhibited when Mgs1 is present. We propose that Mgs1 is necessary to prevent a potentially toxic recombination salvage pathway at sites of perturbed replication, which in turn favors Rad5-dependent template switching, thus helping to preserve genome stability.
2020-04-20 | GSE141712 | GEO
Project description:DNA damage tolerance (DDT) is crucial for genome integrity maintenance. DDT is mainly carried out by template switch recombination, an error-free mode of overcoming DNA lesions, or translesion DNA synthesis, which is error-prone. Here, we investigated the role of Mgs1/WRNIP1 in modulating DDT. Using budding yeast, we found that elimination of Mgs1 in cells lacking Rad5, an essential protein for DDT, activates an alternative mode of DNA damage bypass, driven by recombination, which allows chromosome replication and cell viability under stress conditions that block DNA replication forks. This salvage pathway is RAD52 and RAD59 dependent, requires the DNA polymerase δ and PCNA modification at K164, and is enabled by Esc2 and the PCNA unloader Elg1, being inhibited when Mgs1 is present. We propose that Mgs1 is necessary to prevent a potentially toxic recombination salvage pathway at sites of perturbed replication, which, in turn, favors Rad5-dependent template switching, thus helping to preserve genome stability.
| S-EPMC7141828 | biostudies-literature
Project description:RUVBL1 and RUVBL2 (collectively RUVBL1/2) are essential AAA+ ATPases that function as co-chaperones and have been implicated in cancer. Here we investigated the molecular and phenotypic role of RUVBL1/2 ATPase activity in non-small cell lung cancer (NSCLC). We find that RUVBL1/2 are overexpressed in NSCLC patient tumors, with high expression prognostic of poor survival. Utilizing a highly specific inhibitor of RUVBL1/2 ATPase activity, we show that RUVBL1/2 ATPase activity is necessary for the maturation of the PAQosome, a large RUVBL1/2-dependent multiprotein complex. We also show that RUVBL1/2 have roles in DNA replication, as inhibition of their ATPase activity impedes RPA loading at replication forks, decreases fork stability, and ultimately results in replication catastrophe and cancer cell death. While in vivo pharmacological inhibition of RUVBL1/2 results in modest antitumor activity, it synergizes with radiation in NSCLC, but not normal cells, an attractive property for future preclinical development.
2019-12-18 | GSE107637 | GEO
Project description:Maintenance of NAD+ levels by mitochondrial complex I, the NAD+ salvage pathway, and other routes is an important factor in of neurodegenerative disease and cancer. Both the production of NAD+ and the metabolic enzymes that require it as a redox cofactor or substrate differ widely in abundance across cell types and conditions. Disruption in the NAD+ supply thus exerts different effects depending on the cellular NAD+ requirements existing in the cell. Pharmacological depletion of NAD+ is actively being pursued in cancer and other diseases but these effects are not fully understood. Here, we combine quantitative proteomics and metabolomics to understand the consequences of disrupting cellular NAD+ levels and find that inhibiting the NAD+ salvage pathway depletes serine biosynthesis from glucose by impeding the NAD+-dependent protein 3-phosphoglycerate dehydrogenase (PHGDH). Importantly, breast cancers that depend on PHGDH are exquisitely sensitive to blocking the NAD+ salvage pathway. PHGDH, and the rate-limiting enzyme of NAD+ salvage are also correlated in public tumor proteome and transcript datasets. These findings are immediately translatable to the pharmacological inhibition of NAMPT in PHGDH-dependent cancers.
2018-08-14 | PXD007790 | Pride
Project description:The fidelity of DNA replication is governed by a network of DNA repair mechanisms. Defects in replication fork protection can fuel genome instability in cancer, while also creating cancer-specific vulnerabilities. Here, we provide a comprehensive proteomic characterization of the replication fork response to topoisomerase 1 inhibition, a widely used mainstay chemotherapy. We reveal profound changes in the fork proteome and chromatin environment in response to seDSBs and topological stress, and classify fork repair factors according to their specificity for broken and stalled forks. These distinct fork responses also oppositely affect nucleosome occupancy and nuclear membrane interactions. ATM inhibition dramatically rewired the fork breakage response, revealing that ATM promotes HR-dependent fork restart by concomitantly promoting DNA-end resection and suppressing DSB associated protein ubiquitination and NHEJ. Together, this collection of damaged fork proteomes provides an ample resource to understand fork repair mechanisms and identify druggable targets and novel cancer vulnerabilities.
2021-01-15 | PXD018092 | Pride
Project description:SLFN11 sensitizes cancer cells to a broad range of DNA-targeted therapies. Here we show that, in response to replication stress induced by camptothecin, SLFN11 tightly binds chromatin at stressed replication foci via RPA1 together with the replication helicase subunit MCM3. Unlike ATR, SLFN11 neither interferes with the loading of CDC45 and PCNA nor inhibits the initiation of DNA replication but selectively blocks fork progression while inducing chromatin opening across replication initiation sites. The ATPase domain of SLFN11 is required for chromatin opening, replication block and cell death but not for the tight binding of SLFN11 to chromatin. Replication stress by the CHK1 inhibitor Prexasertib also recruits SLFN11 to nascent replicating DNA together with CDC45 and PCNA. We conclude that SLFN11 is recruited to stressed replication forks carrying extended RPA filaments where it blocks replication by changing chromatin structure across replication sites.
2018-01-18 | GSE101516 | GEO
Project description:SLFN11 sensitizes cancer cells to a broad range of DNA-targeted therapies. Here we show that, in response to replication stress induced by camptothecin, SLFN11 tightly binds chromatin at stressed replication foci via RPA1 together with the replication helicase subunit MCM3. Unlike ATR, SLFN11 neither interferes with the loading of CDC45 and PCNA nor inhibits the initiation of DNA replication but selectively blocks fork progression while inducing chromatin opening across replication initiation sites. The ATPase domain of SLFN11 is required for chromatin opening, replication block and cell death but not for the tight binding of SLFN11 to chromatin. Replication stress by the CHK1 inhibitor Prexasertib also recruits SLFN11 to nascent replicating DNA together with CDC45 and PCNA. We conclude that SLFN11 is recruited to stressed replication forks carrying extended RPA filaments where it blocks replication by changing chromatin structure across replication sites.
2018-01-18 | GSE101512 | GEO
Project description:Regulation of the turnover of complex I (CI), the largest mitochondrial respiratory chain complex remains enigmatic, despite huge advancement in understanding its structure and the assembly steps in recent years. Although some studies indicated that CI might be remodelled in response to various stimuli, the mechanism mediating these putative changes is unknown. Here, we report that the NADH-oxidising N-module which sits on the tip of the CI peripheral arm is turned over at a higher rate and largely independently of the rest of the complex. The N-module turnover is mediated by mitochondrial matrix protease ClpXP, which selectively removes and degrades damaged core subunits. The observed mechanism seems to be a safeguard against accumulation of dysfunctional CI arising from inactivation of the N-module subunits due to attrition caused by extensive redox activity. This CI salvage pathway maintains highly functional CI and healthy mitochondria through an energetically favourable mechanism that demands much lower energetic cost than de novo synthesis and reassembly of the entire CI.
2020-03-05 | PXD014897 | Pride
Project description:Yeast Sen1Senataxin is a RNA/DNA helicase that preserves replication forks across RNA Polymerase II-transcribed genes by counteracting RNA:DNA hybrids accumulation. We show that in Sen1-depleted cells early forks clashing head-on with transcription halt, and impair progression of sister forks within the same replicon. Unsolved replication-transcription collisions trigger the local firing of dormant origins that rescue arrested forks. In sen1 mutants the MRX and Mrc1/Ctf4-complexes protect those forks clashing with transcription by preventing genotoxic fork-resection events mediated by the Exo1 nuclease. Hence, sister forks within the same replicon remain coupled when one of the two forks halts. This is different when forks encounter double strand breaks. Moreover, the local firing of dormant origins is not prevented by checkpoint activation but depends on delayed adjacent forks. Furthermore, a productive head-on clash between replication and transcription requires the tuning of origin firing and coordination between Sen1, the MRX and Mrc1/Ctf4-complexes and Exo1.
2017-10-11 | GSE97046 | GEO
Project description:Long Terminal Repeat (LTR) Retrotransposons are an abundant class of genomic parasites that replicate by insertion of new copies into the host genome. LTR retrotransposons prevent mutagenic insertions through diverse targeting mechanisms that avoid coding sequences, but a universal set of principles guiding their target site selection hasn’t been established. Here we show that insertion of the fission yeast LTR retrotransposon Tf1 is guided by the DNA binding protein Sap1, and that the efficiency and location of the targeting depend on the activity of Sap1 as a replication fork barrier. We propose that Sap1 guides insertion of Tf1 by blocking the progression of the replication fork, and that the Tf1 transposon uses features of arrested forks to insert into the host genome. These observations point to a universal mechanism for determination of LTR retrotransposon target site selection.
2015-09-25 | GSE67692 | GEO