scholarly journals Mcm2-7 Is an Active Player in the DNA Replication Checkpoint Signaling Cascade via Proposed Modulation of Its DNA Gate

2015 ◽  
Vol 35 (12) ◽  
pp. 2131-2143 ◽  
Author(s):  
Feng-Ling Tsai ◽  
Sriram Vijayraghavan ◽  
Joseph Prinz ◽  
Heather K. MacAlpine ◽  
David M. MacAlpine ◽  
...  
Keyword(s):  
Dna Replication ◽  
Conformational Change ◽  
Replication Checkpoint ◽  
Checkpoint Signaling ◽  
Kinase Activation ◽  
Checkpoint Response ◽  
Active Player ◽  
Dna Replication Checkpoint ◽  
Replication Factors

The DNA replication checkpoint (DRC) monitors and responds to stalled replication forks to prevent genomic instability. How core replication factors integrate into this phosphorylation cascade is incompletely understood. Here, through analysis of a uniquemcmallele targeting a specific ATPase active site (mcm2DENQ), we show that the Mcm2-7 replicative helicase has a novel DRC function as part of the signal transduction cascade. This allele exhibits normal downstream mediator (Mrc1) phosphorylation, implying DRC sensor kinase activation. However, the mutant also exhibits defective effector kinase (Rad53) activation and classic DRC phenotypes. Our previousin vitroanalysis showed that themcm2DENQmutation prevents a specific conformational change in the Mcm2-7 hexamer. We infer that this conformational change is required for its DRC role and propose that it allosterically facilitates Rad53 activation to ensure a replication-specific checkpoint response.

The absence of a DNA replication checkpoint in porcine zygotes

Zygote ◽  
2006 ◽  
Vol 14 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Irena Vackova ◽  
Radomir Kren ◽  
Pasqualino Loi ◽  
Vladimír Krylov ◽  
Josef Fulka
Keyword(s):  
Dna Replication ◽  
Intracytoplasmic Sperm Injection ◽  
Sperm Head ◽  
Replication Checkpoint ◽  
Dna Replication Checkpoint

It has been demonstrated that in the zygotes of some mammals a unique checkpoint controls the onset of DNA replication. Thus, DNA replication begins in the maternal pronucleus only after the paternal pronucleus is fully formed. In our experiments we have investigated whether this checkpoint also operates in porcine zygotes produced either by in vitro fertilization (IVF) or by intracytoplasmic sperm injection (ICSI). Our results show that the onset of DNA replication occurs in the maternal pronucleus even in the presence of an intact sperm head in zygotes produced by ICSI, as well as in polyspermic eggs where some sperm heads are intact or male pronuclei are not yet fully developed. We conclude that in porcine zygotes there is an absence of the DNA replication checkpoint that is typical for some other mammals.

scholarly journals Tyrosine Phosphorylation of Cdc2 Is Required for the Replication Checkpoint in Schizosaccharomyces pombe

1998 ◽  
Vol 18 (7) ◽  
pp. 3782-3787 ◽  
Author(s):  
Nicholas Rhind ◽  
Paul Russell
Keyword(s):  
Dna Replication ◽  
Schizosaccharomyces Pombe ◽  
Biochemical Study ◽  
Replication Checkpoint ◽  
Hydroxyurea Treatment ◽  
Activated State ◽  
Dna Replication Checkpoint ◽  
Cdc2 Activity ◽  
In Cells

ABSTRACT The DNA replication checkpoint inhibits mitosis in cells that are unable to replicate their DNA, as when nucleotide biosynthesis is inhibited by hydroxyurea. In the fission yeastSchizosaccharomyces pombe, genetic evidence suggests that this checkpoint involves the inhibition of Cdc2 activity through the phosphorylation of tyrosine-15. On the contrary, a recent biochemical study indicated that Cdc2 is in an activated state during a replication checkpoint, suggesting that phosphorylation of Cdc2 on tyrosine-15 is not part of the replication checkpoint mechanism. We have undertaken biochemical and genetic studies to resolve this controversy. We report that the DNA replication checkpoint in S. pombe is abrogated in cells that carry the allele cdc2-Y15F, expressing an unphosphorylatable form of Cdc2. Furthermore, Cdc2 isolated from replication checkpoint-arrested cells can be activated in vitro by Cdc25, the tyrosine phosphatase responsible for dephosphorylating Cdc2 in vivo, to the same extent as Cdc2 isolated from cdc25ts-blocked cells, indicating that hydroxyurea treatment causes Cdc2 activity to be maintained at a low level that is insufficient to induce mitosis. These studies show that inhibitory tyrosine-15 phosphorylation of Cdc2 is essential for the DNA replication checkpoint and suggests that Cdc25, and/or one or both of Wee1 and Mik1, the tyrosine kinases that phosphorylate Cdc2, are regulated by the replication checkpoint.

scholarly journals DNA Replication Checkpoint Signaling Depends on a Rad53–Dbf4 N-Terminal Interaction in Saccharomyces cerevisiae

Genetics ◽  
2013 ◽  
Vol 194 (2) ◽  
pp. 389-401 ◽  
Author(s):  
Ying-Chou Chen ◽  
Jessica Kenworthy ◽  
Carrie Gabrielse ◽  
Christine Hänni ◽  
Philip Zegerman ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Replication Checkpoint ◽  
Checkpoint Signaling ◽  
Dna Replication Checkpoint

scholarly journals A tel2 Mutation That Destabilizes the Tel2-Tti1-Tti2 Complex Eliminates Rad3ATR Kinase Signaling in the DNA Replication Checkpoint and Leads to Telomere Shortening in Fission Yeast

2019 ◽  
Vol 39 (20) ◽  
Author(s):  
Yong-jie Xu ◽  
Saman Khan ◽  
Adam C. Didier ◽  
Michal Wozniak ◽  
Yufeng Liu ◽  
...  
Keyword(s):  
Dna Replication ◽  
Fission Yeast ◽  
Large Scale ◽  
Gene Encoding ◽  
Telomere Shortening ◽  
Signaling Mechanism ◽  
Replication Checkpoint ◽  
Checkpoint Signaling ◽  
Enhanced Sensitivity ◽  
Dna Replication Checkpoint

ABSTRACT In response to perturbed DNA replication, ATR (ataxia telangiectasia and Rad3-related) kinase is activated to initiate the checkpoint signaling necessary for maintaining genome integrity and cell survival. To better understand the signaling mechanism, we carried out a large-scale genetic screen in fission yeast looking for mutants with enhanced sensitivity to hydroxyurea. From a collection of ∼370 primary mutants, we found a few mutants in which Rad3 (ATR ortholog)-mediated phospho-signaling was significantly compromised. One such mutant carried an uncharacterized mutation in tel2, a gene encoding an essential and highly conserved eukaryotic protein. Previous studies in various biological models have shown that Tel2 mainly functions in Tel2-Tti1-Tti2 (TTT) complex that regulates the steady-state levels of all phosphatidylinositol 3-kinase-like protein kinases, including ATR. We show here that although the levels of Rad3 and Rad3-mediated phospho-signaling in DNA damage checkpoint were moderately reduced in the tel2 mutant, the phospho-signaling in the DNA replication checkpoint was almost completely eliminated. In addition, the tel2 mutation caused telomere shortening. Since the interactions of Tel2 with Tti1 and Tti2 were significantly weakened by the mutation, destabilization of the TTT complex likely contributes to the observed checkpoint and telomere defects.

The DNA replication checkpoint response stabilizes stalled replication forks

Nature ◽  
2001 ◽  
Vol 412 (6846) ◽  
pp. 557-561 ◽  
Author(s):  
Massimo Lopes ◽  
Cecilia Cotta-Ramusino ◽  
Achille Pellicioli ◽  
Giordano Liberi ◽  
Paolo Plevani ◽  
...  
Keyword(s):  
Dna Replication ◽  
Replication Forks ◽  
Replication Checkpoint ◽  
Checkpoint Response ◽  
Dna Replication Checkpoint ◽  
Stalled Replication Forks

Dpb11/TopBP1 plays distinct roles in DNA replication, checkpoint response and homologous recombination

DNA Repair ◽  
2011 ◽  
Vol 10 (2) ◽  
pp. 210-224 ◽  
Author(s):  
Susanne M. Germann ◽  
Vibe H. Oestergaard ◽  
Caroline Haas ◽  
Pauline Salis ◽  
Akira Motegi ◽  
...  
Keyword(s):  
Dna Replication ◽  
Homologous Recombination ◽  
Replication Checkpoint ◽  
Checkpoint Response ◽  
Dna Replication Checkpoint

scholarly journals The yeast Sgs1p helicase acts upstream of Rad53p in the DNA replication checkpoint and colocalizes with Rad53p in S-phase-specific foci

2000 ◽  
Vol 14 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Christian Frei ◽  
Susan M. Gasser
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Replication Fork ◽  
Dna Helicase ◽  
S Phase ◽  
Replication Checkpoint ◽  
Checkpoint Response ◽  
Replication Fork Progression ◽  
Cycle Arrest ◽  
Dna Replication Checkpoint

We have examined the cellular function of Sgs1p, a nonessential yeast DNA helicase, homologs of which are implicated in two highly debilitating hereditary human diseases (Werner's and Bloom's syndromes). We show that Sgs1p is an integral component of the S-phase checkpoint response in yeast, which arrests cells due to DNA damage or blocked fork progression during DNA replication. DNA polε and Sgs1p are found in the same epistasis group and act upstream of Rad53p to signal cell cycle arrest when DNA replication is perturbed. Sgs1p is tightly regulated through the cell cycle, accumulates in S phase and colocalizes with Rad53p in S-phase-specific foci, even in the absence of fork arrest. The association of Rad53p with a chromatin subfraction is Sgs1p dependent, suggesting an important role for the helicase in the signal-transducing pathway that monitors replication fork progression.

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