scholarly journals The activation loop residue serine 173 of S.pombe Chk1 kinase is critical for the response to DNA replication stress

2017 ◽  
Author(s):  
Naomi Coulton ◽  
Thomas Caspari

AbstractWhy the DNA damage checkpoint kinase Chk1 protects the genome of lower and higher eukaryotic cells differentially is still unclear. Mammalian Chk1 regulates replication origins, safeguards DNA replication forks and promotes fork progression. Conversely, yeast Chk1 acts only in G1 and G2. We report here that the mutation of serine 173 (S173A) in the activation loop of fission yeast Chk1 abolishes the G1-M and S-M checkpoints without affecting the G2-M arrest. Although Chk1-S173A is fully phosphorylated at serine 345 by the DNA damage sensor Rad3 (ATR) when DNA replication forks break, cells fail to stop the cell cycle. Mutant cells are uniquely sensitive to the DNA alkylation agent methyl- methanesulfate (MMS). This MMS sensitivity is genetically linked with the lagging strand DNA polymerase delta. Chk1-S173A is also unable to block mitosis when the G1 transcription factor Cdc10 is impaired. Serine 173 is equivalent to lysine 166 in human Chk1, an amino acid important for substrate specificity. We conclude that the removal of serine 173 impairs the phosphorylation of a Chk1 target that is important to protect cells from DNA replication stress.Summary statementMutation of serine-173 in the activation loop of Chk1 kinase may promote cancer as it abolishes the response to genetic alterations that arise while chromosomes are being copied.

Science ◽  
2013 ◽  
Vol 343 (6166) ◽  
pp. 88-91 ◽  
Author(s):  
Lorenzo Costantino ◽  
Sotirios K. Sotiriou ◽  
Juha K. Rantala ◽  
Simon Magin ◽  
Emil Mladenov ◽  
...  

In budding yeast, one-ended DNA double-strand breaks (DSBs) and damaged replication forks are repaired by break-induced replication (BIR), a homologous recombination pathway that requires the Pol32 subunit of DNA polymerase delta. DNA replication stress is prevalent in cancer, but BIR has not been characterized in mammals. In a cyclin E overexpression model of DNA replication stress, POLD3, the human ortholog of POL32, was required for cell cycle progression and processive DNA synthesis. Segmental genomic duplications induced by cyclin E overexpression were also dependent on POLD3, as were BIR-mediated recombination events captured with a specialized DSB repair assay. We propose that BIR repairs damaged replication forks in mammals, accounting for the high frequency of genomic duplications in human cancers.


Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 730
Author(s):  
Clara Forrer Charlier ◽  
Rodrigo A. P. Martins

The precise replication of DNA and the successful segregation of chromosomes are essential for the faithful transmission of genetic information during the cell cycle. Alterations in the dynamics of genome replication, also referred to as DNA replication stress, may lead to DNA damage and, consequently, mutations and chromosomal rearrangements. Extensive research has revealed that DNA replication stress drives genome instability during tumorigenesis. Over decades, genetic studies of inherited syndromes have established a connection between the mutations in genes required for proper DNA repair/DNA damage responses and neurological diseases. It is becoming clear that both the prevention and the responses to replication stress are particularly important for nervous system development and function. The accurate regulation of cell proliferation is key for the expansion of progenitor pools during central nervous system (CNS) development, adult neurogenesis, and regeneration. Moreover, DNA replication stress in glial cells regulates CNS tumorigenesis and plays a role in neurodegenerative diseases such as ataxia telangiectasia (A-T). Here, we review how replication stress generation and replication stress response (RSR) contribute to the CNS development, homeostasis, and disease. Both cell-autonomous mechanisms, as well as the evidence of RSR-mediated alterations of the cellular microenvironment in the nervous system, were discussed.


2020 ◽  
Vol 48 (22) ◽  
pp. 12711-12726
Author(s):  
Yuanliang Yan ◽  
Zhijie Xu ◽  
Jinzhou Huang ◽  
Guijie Guo ◽  
Ming Gao ◽  
...  

Abstract PrimPol has been recently identified as a DNA damage tolerant polymerase that plays an important role in replication stress response. However, the regulatory mechanisms of PrimPol are not well defined. In this study, we identify that the deubiquitinase USP36 interferes with degradation of PrimPol to regulate the replication stress response. Mechanistically, USP36 is deubiquitinated following DNA replication stress, which in turn facilitates its upregulation and interaction with PrimPol. USP36 deubiquitinates K29-linked polyubiquitination of PrimPol and increases its protein stability. Depletion of USP36 results in replication stress-related defects and elevates cell sensitivity to DNA-damage agents, such as cisplatin and olaparib. Moreover, USP36 expression positively correlates with the level of PrimPol protein and poor prognosis in patient samples. These findings indicate that the regulation of PrimPol K29-linked ubiquitination by USP36 plays a critical role in DNA replication stress and chemotherapy response.


2009 ◽  
Vol 20 (3) ◽  
pp. 983-994 ◽  
Author(s):  
Xia Yi ◽  
Hilda I. de Vries ◽  
Katarzyna Siudeja ◽  
Anil Rana ◽  
Willy Lemstra ◽  
...  

Hydroxyurea, a well-known DNA replication inhibitor, induces cell cycle arrest and intact checkpoint functions are required to survive DNA replication stress induced by this genotoxic agent. Perturbed DNA synthesis also results in elevated levels of DNA damage. It is unclear how organisms prevent accumulation of this type of DNA damage that coincides with hampered DNA synthesis. Here, we report the identification of stonewall (stwl) as a novel hydroxyurea-hypersensitive mutant. We demonstrate that Stwl is required to prevent accumulation of DNA damage induced by hydroxyurea; yet, Stwl is not involved in S/M checkpoint regulation. We show that Stwl is a heterochromatin-associated protein with transcription-repressing capacities. In stwl mutants, levels of trimethylated H3K27 and H3K9 (two hallmarks of silent chromatin) are decreased. Our data provide evidence for a Stwl-dependent epigenetic mechanism that is involved in the maintenance of the normal balance between euchromatin and heterochromatin and that is required to prevent accumulation of DNA damage in the presence of DNA replication stress.


2012 ◽  
Vol 14 (9) ◽  
pp. 966-976 ◽  
Author(s):  
Johnny M. Tkach ◽  
Askar Yimit ◽  
Anna Y. Lee ◽  
Michael Riffle ◽  
Michael Costanzo ◽  
...  

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Marco Fumasoni ◽  
Andrew W Murray

Many biological features are conserved and thus considered to be resistant to evolutionary change. While rapid genetic adaptation following the removal of conserved genes has been observed, we often lack a mechanistic understanding of how adaptation happens. We used the budding yeast, Saccharomyces cerevisiae, to investigate the evolutionary plasticity of chromosome metabolism, a network of evolutionary conserved modules. We experimentally evolved cells constitutively experiencing DNA replication stress caused by the absence of Ctf4, a protein that coordinates the enzymatic activities at replication forks. Parallel populations adapted to replication stress, over 1000 generations, by acquiring multiple, concerted mutations. These mutations altered conserved features of two chromosome metabolism modules, DNA replication and sister chromatid cohesion, and inactivated a third, the DNA damage checkpoint. The selected mutations define a functionally reproducible evolutionary trajectory. We suggest that the evolutionary plasticity of chromosome metabolism has implications for genome evolution in natural populations and cancer.


2020 ◽  
Author(s):  
Zainab Tayeh ◽  
Kim Stegmann ◽  
Antonia Kleeberg ◽  
Mascha Friedrich ◽  
Josephine Ann Mun Yee Choo ◽  
...  

AbstractCentrosomes function as organizing centers of microtubules and support accurate mitosis in many animal cells. However, it remains to be explored whether and how centrosomes also facilitate the progression through different phases of the cell cycle. Here we show that impairing the composition of centrosomes, by depletion of centrosomal components or by inhibition of polo-like kinase 4 (PLK4), reduces the progression of DNA replication forks. This occurs even when the cell cycle is arrested before damaging the centrosomes, thus excluding mitotic failure as the source of replication stress. Mechanistically, the kinase MLK3 associates with centrosomes. When centrosomes are disintegrated, MLK3 activates the kinases p38 and MK2/MAPKAPK2. Transcription-dependent RNA:DNA hybrids (R-loops) are then causing DNA replication stress. Fibroblasts from patients with microcephalic primordial dwarfism (Seckel syndrome) harbouring defective centrosomes showed replication stress and diminished proliferation, which were each alleviated by inhibition of MK2. Thus, centrosomes not only facilitate mitosis, but their integrity is also supportive in DNA replication.HighlightsCentrosome defects cause replication stress independent of mitosis.MLK3, p38 and MK2 (alias MAPKAPK2) are signalling between centrosome defects and DNA replication stress through R-loop formation.Patient-derived cells with defective centrosomes display replication stress, whereas inhibition of MK2 restores their DNA replication fork progression and proliferation.Graphical abstract


Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 990 ◽  
Author(s):  
Huanbo Zhu ◽  
Umang Swami ◽  
Ranjan Preet ◽  
Jun Zhang

DNA replication is the fundamental process for accurate duplication and transfer of genetic information. Its fidelity is under constant stress from endogenous and exogenous factors which can cause perturbations that lead to DNA damage and defective replication. This can compromise genomic stability and integrity. Genomic instability is considered as one of the hallmarks of cancer. In normal cells, various checkpoints could either activate DNA repair or induce cell death/senescence. Cancer cells on the other hand potentiate DNA replicative stress, due to defective DNA damage repair mechanism and unchecked growth signaling. Though replicative stress can lead to mutagenesis and tumorigenesis, it can be harnessed paradoxically for cancer treatment. Herein, we review the mechanism and rationale to exploit replication stress for cancer therapy. We discuss both established and new approaches targeting DNA replication stress including chemotherapy, radiation, and small molecule inhibitors targeting pathways including ATR, Chk1, PARP, WEE1, MELK, NAE, TLK etc. Finally, we review combination treatments, biomarkers, and we suggest potential novel methods to target DNA replication stress to treat cancer.


2019 ◽  
Vol 79 (7) ◽  
pp. 1612-1623 ◽  
Author(s):  
Matthew V. Puccetti ◽  
Clare M. Adams ◽  
Saul Kushinsky ◽  
Christine M. Eischen

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