Dataset Information

Unresolved Recombination Intermediates Cause a RAD9-Dependent Cell Cycle Arrest in Saccharomyces cerevisiae.

ABSTRACT: In Saccharomyces cerevisiae, the conserved Sgs1-Top3-Rmi1 helicase-decatenase regulates homologous recombination by limiting accumulation of recombination intermediates that are crossover precursors. In vitro studies have suggested that this may be due to dissolution of double-Holliday junction joint molecules by Sgs1-driven convergent junction migration and Top3-Rmi1 mediated strand decatenation. To ask whether dissolution occurs in vivo, we conditionally depleted Sgs1 and/or Rmi1 during return to growth (RTG), a procedure where recombination intermediates formed during meiosis are resolved when cells resume the mitotic cell cycle. Sgs1 depletion during RTG delayed joint molecule resolution, but, ultimately, most were resolved and cells divided normally. In contrast, Rmi1 depletion resulted in delayed and incomplete joint molecule resolution, and most cells did not divide. rad9 ? mutation restored cell division in Rmi1-depleted cells, indicating that the DNA damage checkpoint caused this cell cycle arrest. Restored cell division in Rmi1-depleted rad9 ? cells frequently produced anucleate cells, consistent with the suggestion that persistent recombination intermediates prevented chromosome segregation. Our findings indicate that Sgs1-Top3-Rmi1 acts in vivo, as it does in vitro, to promote recombination intermediate resolution by dissolution. They also indicate that, in the absence of Top3-Rmi1 activity, unresolved recombination intermediates persist and activate the DNA damage response, which is usually thought to be activated by much earlier DNA damage-associated lesions.

SUBMITTER: Kaur H

PROVIDER: S-EPMC6827386 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Unresolved Recombination Intermediates Cause a RAD9-Dependent Cell Cycle Arrest in Saccharomyces cerevisiae.

Kaur Hardeep H Gn Krishnaprasad K Lichten Michael M

Genetics 20190927 3

In Saccharomyces cerevisiae, the conserved Sgs1-Top3-Rmi1 helicase-decatenase regulates homologous recombination by limiting accumulation of recombination intermediates that are crossover precursors. In vitro studies have suggested that this may be due to dissolution of double-Holliday junction joint molecules by Sgs1-driven convergent junction migration and Top3-Rmi1 mediated strand decatenation. To ask whether dissolution occurs in vivo, we conditionally depleted Sgs1 and/ ...[more]

PMID: 31562181

Similar Datasets

Project description:In cells lacking telomerase, telomeres shorten progressively during each cell division due to incomplete end-replication. When the telomeres become very short, cells enter a state that blocks cell division, termed senescence. A subset of these cells can overcome senescence and maintain their telomeres using telomerase-independent mechanisms. In Saccharomyces cerevisiae, these cells are called 'survivors' and are dependent on Rad52-dependent homologous recombination and Pol32-dependent break-induced replication. There are two main types of survivors: type I and type II. The type I survivors require Rad51 and maintain telomeres by amplification of subtelomeric elements, while the type II survivors are Rad51-independent, but require the MRX complex and Sgs1 to amplify the C1-3A/TG1-3 telomeric sequences. Rad52, Pol32, Rad51, and Sgs1 are also important to prevent accelerated senescence, indicating that recombination processes are important at telomeres even before the formation of survivors. The Shu complex, which consists of Shu1, Shu2, Psy3, and Csm2, promotes Rad51-dependent homologous recombination and has been suggested to be important for break-induced replication. It also promotes the formation of recombination intermediates that are processed by the Sgs1-Top3-Rmi1 complex, as mutations in the SHU genes can suppress various sgs1, top3, and rmi1 mutant phenotypes. Given the importance of recombination processes during senescence and survivor formation, and the involvement of the Shu complex in many of the same processes during DNA repair, we hypothesized that the Shu complex may also have functions at telomeres. Surprisingly, we find that this is not the case: the Shu complex does not affect the rate of senescence, does not influence survivor formation, and deletion of SHU1 does not suppress the rapid senescence and type II survivor formation defect of a telomerase-negative sgs1 mutant. Altogether, our data suggest that the Shu complex is not important for recombination processes at telomeres.

Dataset Information

Unresolved Recombination Intermediates Cause a RAD9-Dependent Cell Cycle Arrest in Saccharomyces cerevisiae.

Publications

Unresolved Recombination Intermediates Cause a <i>RAD9</i>-Dependent Cell Cycle Arrest in <i>Saccharomyces cerevisiae</i>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets