scholarly journals Cdc28/Cdk1 positively and negatively affects genome stability in S. cerevisiae

2009 ◽  
Vol 185 (3) ◽  
pp. 423-437 ◽  
Author(s):  
Jorrit M. Enserink ◽  
Hans Hombauer ◽  
Meng-Er Huang ◽  
Richard D. Kolodner
Keyword(s):  
Dna Damage ◽  
Cell Viability ◽  
Genome Stability ◽  
Chromosomal Rearrangements ◽  
Genetic Network ◽  
Telomere Maintenance ◽  
Mitotic Catastrophe ◽  
Chemical Genetic ◽  
Replication Arrest ◽  
Gross Chromosomal Rearrangements

We studied the function of the cyclin-dependent kinase Cdc28 (Cdk1) in the DNA damage response and maintenance of genome stability using Saccharomyces cerevisiae. Reduced Cdc28 activity sensitizes cells to chronic DNA damage, but Cdc28 is not required for cell viability upon acute exposure to DNA-damaging agents. Cdc28 is also not required for activation of the DNA damage and replication checkpoints. Chemical–genetic analysis reveals that CDC28 functions in an extensive network of pathways involved in maintenance of genome stability, including homologous recombination, sister chromatid cohesion, the spindle checkpoint, postreplication repair, and telomere maintenance. In addition, Cdc28 and Mre11 appear to cooperate to prevent mitotic catastrophe after DNA replication arrest. We show that reduced Cdc28 activity results in suppression of gross chromosomal rearrangements (GCRs), indicating that Cdc28 is required for formation or recovery of GCRs. Thus, we conclude that Cdc28 functions in a genetic network that supports cell viability during DNA damage while promoting the formation of GCRs.

Understanding the functions of BRCA1 in the DNA-damage response

2009 ◽  
Vol 37 (3) ◽  
pp. 597-604 ◽  
Author(s):  
Maximina H. Yun ◽  
Kevin Hiom
Keyword(s):  
Dna Damage ◽  
Early Onset ◽  
Genome Stability ◽  
Chromosomal Rearrangements ◽  
Dna Lesions ◽  
Cell Cycle Checkpoints ◽  
Dna Breaks ◽  
Gross Chromosomal Rearrangements ◽  
Damage Response ◽  
Regulation Of Cell Cycle

Inheritance of a mutation in BRCA1 (breast cancer 1 early-onset) results in predisposition to early-onset breast and ovarian cancer. Tumours in these individuals arise after somatic mutation or loss of the wild-type allele. Loss of BRCA1 function leads to a profound increase in genomic instability involving the accumulation of mutations, DNA breaks and gross chromosomal rearrangements. Accordingly, BRCA1 has been implicated as an important factor involved in both the repair of DNA lesions and in the regulation of cell-cycle checkpoints in response to DNA damage. However, the molecular mechanism through which BRCA1 functions to preserve genome stability remains unclear. In the present article, we examine the different ways in which BRCA1 might influence the repair of DNA damage and the preservation of genome integrity, taking into account what is currently known about its interactions with other proteins, its biochemical activity and its nuclear localization.

scholarly journals Inactivation of folylpolyglutamate synthetase Met7 results in genome instability driven by an increased dUTP/dTTP ratio

2019 ◽  
Author(s):  
Tobias T Schmidt ◽  
Sushma Sharma ◽  
Gloria X Reyes ◽  
Anna Kolodziejczak ◽  
Tina Wagner ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genome Stability ◽  
Nuclear Dna ◽  
Genome Instability ◽  
Chromosomal Rearrangements ◽  
Dna Integrity ◽  
Folylpolyglutamate Synthetase ◽  
Cell Extracts ◽  
Gross Chromosomal Rearrangements ◽  
The Stability

Abstract The accumulation of mutations is frequently associated with alterations in gene function leading to the onset of diseases, including cancer. Aiming to find novel genes that contribute to the stability of the genome, we screened the Saccharomyces cerevisiae deletion collection for increased mutator phenotypes. Among the identified genes, we discovered MET7, which encodes folylpolyglutamate synthetase (FPGS), an enzyme that facilitates several folate-dependent reactions including the synthesis of purines, thymidylate (dTMP) and DNA methylation. Here, we found that Met7-deficient strains show elevated mutation rates, but also increased levels of endogenous DNA damage resulting in gross chromosomal rearrangements (GCRs). Quantification of deoxyribonucleotide (dNTP) pools in cell extracts from met7Δ mutant revealed reductions in dTTP and dGTP that cause a constitutively active DNA damage checkpoint. In addition, we found that the absence of Met7 leads to dUTP accumulation, at levels that allowed its detection in yeast extracts for the first time. Consequently, a high dUTP/dTTP ratio promotes uracil incorporation into DNA, followed by futile repair cycles that compromise both mitochondrial and nuclear DNA integrity. In summary, this work highlights the importance of folate polyglutamylation in the maintenance of nucleotide homeostasis and genome stability.

scholarly journals The Saccharomyces cerevisiae Rad6 Postreplication Repair and Siz1/Srs2 Homologous Recombination-Inhibiting Pathways Process DNA Damage That Arises in asf1 Mutants

2009 ◽  
Vol 29 (19) ◽  
pp. 5226-5237 ◽  
Author(s):  
Ellen S. Kats ◽  
Jorrit M. Enserink ◽  
Sandra Martinez ◽  
Richard D. Kolodner
Keyword(s):  
Homologous Recombination ◽  
Genome Stability ◽  
Chromosomal Rearrangements ◽  
Nuclear Antigen ◽  
Recombination Suppression ◽  
Postreplication Repair ◽  
Gross Chromosomal Rearrangements ◽  
Translesion Bypass ◽  
The Relationship ◽  
Proliferating Cell

ABSTRACT The Asf1 and Rad6 pathways have been implicated in a number of common processes such as suppression of gross chromosomal rearrangements (GCRs), DNA repair, modification of chromatin, and proper checkpoint functions. We examined the relationship between Asf1 and different gene products implicated in postreplication repair (PRR) pathways in the suppression of GCRs, checkpoint function, sensitivity to hydroxyurea (HU) and methyl methanesulfonate (MMS), and ubiquitination of proliferating cell nuclear antigen (PCNA). We found that defects in Rad6 PRR pathway and Siz1/Srs2 homologous recombination suppression (HRS) pathway genes suppressed the increased GCR rates seen in asf1 mutants, which was independent of translesion bypass polymerases but showed an increased dependency on Dun1. Combining an asf1 deletion with different PRR mutations resulted in a synergistic increase in sensitivity to chronic HU and MMS treatment; however, these double mutants were not checkpoint defective, since they were capable of recovering from acute treatment with HU. Interestingly, we found that Asf1 and Rad6 cooperate in ubiquitination of PCNA, indicating that Rad6 and Asf1 function in parallel pathways that ubiquitinate PCNA. Our results show that ASF1 probably contributes to the maintenance of genome stability through multiple mechanisms, some of which involve the PRR and HRS pathways.

scholarly journals Zika virus induces mitotic catastrophe in human neural progenitors by triggering unscheduled mitotic entry in the presence of DNA damage while functionally depleting nuclear PNKP

2021 ◽  
Author(s):  
Malgorzata Rychlowska ◽  
Abigail Agyapong ◽  
Michael Weinfeld ◽  
Luis M Schang
Keyword(s):  
Dna Damage ◽  
Zika Virus ◽  
Cortical Neurons ◽  
Genome Stability ◽  
Neural Progenitor Cells ◽  
Cellular Level ◽  
Mitotic Catastrophe ◽  
Zikv Infection ◽  
Mitotic Entry ◽  
Checkpoint Kinases

Vertical transmission of Zika virus (ZIKV) leads with high frequency to congenital ZIKV syndrome (CZS), whose worse outcome is microcephaly. However, the mechanisms of congenital ZIKV neurodevelopmental pathologies, including direct cytotoxicity to neural progenitor cells (NPC), placental insufficiency, and immune responses, remain incompletely understood. At the cellular level, microcephaly typically results from death or insufficient proliferation of NPC or cortical neurons. NPCs replicate fast, requiring efficient DNA damage responses to ensure genome stability. Like congenital ZIKV infection, mutations in the polynucleotide 5’-kinase 3’-phosphatase (PNKP) gene, which encodes a critical DNA damage repair enzyme, results in recessive syndromes often characterized by congenital microcephaly with seizures (MCSZ). We thus tested whether there were any links between ZIKV and PNKP. Here we show that a PNKP phosphatase inhibitor inhibits ZIKV replication. PNKP relocalized from the nucleus to the cytoplasm in infected cells, co-localizing with the marker of ZIKV replication factories (RF) NS1 and resulting in functional nuclear PNKP depletion. Although infected NPC accumulated DNA damage, they failed to activate the DNA damage checkpoint kinases Chk1 and Chk2. ZIKV also induced activation of cytoplasmic CycA/CDK1 complexes, which trigger unscheduled mitotic entry. Inhibition of CDK1 activity inhibited ZIKV replication and the formation of RF, supporting a role of cytoplasmic CycA/CDK1 in RF morphogenesis. In brief, ZIKV infection induces mitotic catastrophe resulting from unscheduled mitotic entry in the presence of DNA damage. PNKP and CycA/CDK1 are thus host factors participating in ZIKV replication in NPC, and probably pathogenesis.

scholarly journals The Relevance of G-Quadruplexes for DNA Repair

2021 ◽  
Vol 22 (22) ◽  
pp. 12599
Author(s):  
Rebecca Linke ◽  
Michaela Limmer ◽  
Stefan Juranek ◽  
Annkristin Heine ◽  
Katrin Paeschke
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Genome Stability ◽  
Genome Instability ◽  
Genetic Disorders ◽  
Telomere Maintenance ◽  
Dna Structures ◽  
G4 Dna ◽  
G Quadruplex ◽  
Repair Pathways

DNA molecules can adopt a variety of alternative structures. Among these structures are G-quadruplex DNA structures (G4s), which support cellular function by affecting transcription, translation, and telomere maintenance. These structures can also induce genome instability by stalling replication, increasing DNA damage, and recombination events. G-quadruplex-driven genome instability is connected to tumorigenesis and other genetic disorders. In recent years, the connection between genome stability, DNA repair and G4 formation was further underlined by the identification of multiple DNA repair proteins and ligands which bind and stabilize said G4 structures to block specific DNA repair pathways. The relevance of G4s for different DNA repair pathways is complex and depends on the repair pathway itself. G4 structures can induce DNA damage and block efficient DNA repair, but they can also support the activity and function of certain repair pathways. In this review, we highlight the roles and consequences of G4 DNA structures for DNA repair initiation, processing, and the efficiency of various DNA repair pathways.

scholarly journals At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 118 ◽  
Author(s):  
Anna Y. Aksenova ◽  
Sergei M. Mirkin
Keyword(s):  
Genome Stability ◽  
Dynamic Properties ◽  
Chromosomal Rearrangements ◽  
Dna Repeats ◽  
Telomeric Dna ◽  
Telomeric Sequences ◽  
Gross Chromosomal Rearrangements ◽  
Interstitial Telomeric Sequences ◽  
Chromosomal Fragility ◽  
Living Organisms

Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.

scholarly journals Multifunctional Role of ATM/Tel1 Kinase in Genome Stability: From the DNA Damage Response to Telomere Maintenance

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Enea Gino Di Domenico ◽  
Elena Romano ◽  
Paola Del Porto ◽  
Fiorentina Ascenzioni
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Ataxia Telangiectasia ◽  
Genome Stability ◽  
Genetic Disorder ◽  
Cell Cycle Control ◽  
Premature Aging ◽  
Telomere Maintenance ◽  
Damage Response

The mammalian protein kinase ataxia telangiectasia mutated (ATM) is a key regulator of the DNA double-strand-break response and belongs to the evolutionary conserved phosphatidylinositol-3-kinase-related protein kinases. ATM deficiency causes ataxia telangiectasia (AT), a genetic disorder that is characterized by premature aging, cerebellar neuropathy, immunodeficiency, and predisposition to cancer. AT cells show defects in the DNA damage-response pathway, cell-cycle control, and telomere maintenance and length regulation. Likewise, inSaccharomyces cerevisiae, haploid strains defective in theTEL1gene, the ATM ortholog, show chromosomal aberrations and short telomeres. In this review, we outline the complex role of ATM/Tel1 in maintaining genomic stability through its control of numerous aspects of cellular survival. In particular, we describe how ATM/Tel1 participates in the signal transduction pathways elicited by DNA damage and in telomere homeostasis and its importance as a barrier to cancer development.

scholarly journals Functions of Saccharomyces cerevisiae 14-3-3 Proteins in Response to DNA Damage and to DNA Replication Stress

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1717-1732
Author(s):  
Francisca Lottersberger ◽  
Fabio Rubert ◽  
Veronica Baldo ◽  
Giovanna Lucchini ◽  
Maria Pia Longhese
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Dna Replication ◽  
Genome Instability ◽  
Chromosomal Rearrangements ◽  
Replication Stress ◽  
Checkpoint Kinases ◽  
Gross Chromosomal Rearrangements ◽  
Dna Damage Checkpoints ◽  
Dna Replication Stress

Abstract Two members of the 14-3-3 protein family, involved in key biological processes in different eukaryotes, are encoded by the functionally redundant Saccharomyces cerevisiae BMH1 and BMH2 genes. We produced and characterized 12 independent bmh1 mutant alleles, whose presence in the cell as the sole 14-3-3 source causes hypersensitivity to genotoxic agents, indicating that Bmh proteins are required for proper response to DNA damage. In particular, the bmh1-103 and bmh1-266 mutant alleles cause defects in G1/S and G2/M DNA damage checkpoints, whereas only the G2/M checkpoint is altered by the bmh1-169 and bmh1-221 alleles. Impaired checkpoint responses correlate with the inability to maintain phosphorylated forms of Rad53 and/or Chk1, suggesting that Bmh proteins might regulate phosphorylation/dephosphorylation of these checkpoint kinases. Moreover, several bmh1 bmh2Δ mutants are defective in resuming DNA replication after transient deoxynucleotide depletion, and all display synthetic effects when also carrying mutations affecting the polα-primase and RPA DNA replication complexes, suggesting a role for Bmh proteins in DNA replication stress response. Finally, the bmh1-169 bmh2Δ and bmh1-170 bmh2Δ mutants show increased rates of spontaneous gross chromosomal rearrangements, indicating that Bmh proteins are required to suppress genome instability.

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