scholarly journals A Novel Function of the DNA Repair Gene rhp6 in Mating-Type Silencing by Chromatin Remodeling in Fission Yeast

1998 ◽  
Vol 18 (9) ◽  
pp. 5511-5522 ◽  
Author(s):  
Jagmohan Singh ◽  
Vintoo Goel ◽  
Amar J. S. Klar
Keyword(s):  
Dna Repair ◽  
Gene Regulation ◽  
Dna Replication ◽  
Mating Type ◽  
Chromatin Structure ◽  
Temperature Sensitive ◽  
Repair Gene ◽  
Daughter Cells ◽  
Dna Repair Gene

ABSTRACT Recent studies have indicated that the DNA replication machinery is coupled to silencing of mating-type loci in the budding yeastSaccharomyces cerevisiae, and a similar silencing mechanism may operate in the distantly related yeast Schizosaccharomyces pombe. Regarding gene regulation, an important function of DNA replication may be in coupling of faithful chromatin assembly to reestablishment of the parental states of gene expression in daughter cells. We have been interested in isolating mutants that are defective in this hypothesized coupling. An S. pombe mutant fortuitously isolated from a screen for temperature-sensitive growth and silencing phenotype exhibited a novel defect in silencing that was dependent on the switching competence of the mating-type loci, a property that differentiates this mutant from other silencing mutants of S. pombe as well as of S. cerevisiae. This unique mutant phenotype defined a locus which we named sng1 (for silencing not governed). Chromatin analysis revealed a switching-dependent unfolding of the donor locimat2P and mat3M in thesng1 − mutant, as indicated by increased accessibility to the in vivo-expressed Escherichia coli dammethylase. Unexpectedly, cloning and sequencing identified the gene as the previously isolated DNA repair gene rhp6. RAD6, an rhp6 homolog in S. cerevisiae, is required for postreplication DNA repair and ubiquitination of histones H2A and H2B. This study implicates the Rad6/rhp6 protein in gene regulation and, more importantly, suggests that a transient window of opportunity exists to ensure the remodeling of chromatin structure during chromosome replication and recombination. We propose that the effects of thesng1−/rhp6 − mutation on silencing are indirect consequences of changes in chromatin structure.

Isolation of a Schizosaccharomyces pombe rad21ts Mutant That Is Aberrant in Chromosome Segregation, Microtubule Function, DNA Repair and Sensitive to Hydroxyurea: Possible Involvement of Rad21 in Ubiquitin-Mediated Proteolysis

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 49-57
Author(s):  
Kazuo Tatebayashi ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Dna Repair ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Repair Gene ◽  
Tubulin Genes ◽  
Gene Coding ◽  
Abnormal Mitosis ◽  
Dna Repair Gene ◽  
Nuclear Structures ◽  
Microtubule Function

Abstract The fission yeast DNA repair gene rad21+ is essential for cell growth. To investigate the function essential for cell proliferation, we have isolated a temperature-sensitive mutant of the rad21+ gene. The mutant, rad21-K1, showed abnormal mitosis at the nonpermissive temperature. Some cells contained abnormal nuclear structures, such as condensed chromosomes with short spindles, or chromosomes stretched or unequally separated by elongating spindles. Other cells exhibited the displaced nucleus or a cut-like phenotype. Similar abnormalities were observed when the Rad21 protein was depleted from cells. We therefore concluded that Rad21 is essential for proper segregation of chromosomes. Moreover, the rad21-K1 mutant is sensitive not only to UV and γ-ray irradiation but to thiabendazole and hydroxyurea, indicating that Rad21 plays important roles in microtubule function, DNA repair, and S phase function. The relation to the microtubule function was further confirmed by the fact that rad21+ genetically interacts with tubulin genes, nda2+ and nda3+. Finally, the growth of the rad21-K1 mutant was inhibited at the permissive temperature by introduction of another mutation in the cut9+ gene, coding for a component of the 20S cyclosome/anaphase promoting complex, which is involved in ubiquitin-mediated proteolysis. The results suggest that these diverse functions of Rad21 may be facilitated through ubiquitin-mediated proteolysis.

scholarly journals Crystal structure of the ATPase-C domain of the chromatin remodeller Fun30 fromSaccharomyces cerevisiae

2017 ◽  
Vol 73 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Lan Liu ◽  
Tao Jiang
Keyword(s):  
Crystal Structure ◽  
Dna Repair ◽  
Gene Silencing ◽  
Chromatin Structure ◽  
Family Members ◽  
Atpase Domain ◽  
Repair Gene ◽  
Dna Repair Gene

Fun30 (Function unknown now 30) is a chromatin remodeller belonging to the Snf2 family. It has previously been reported to be a regulator of several cellular activities, including DNA repair, gene silencing and maintenance of chromatin structure. Here, the crystal structure of the Fun30 ATPase-C domain (the C-lobe of the ATPase domain) is reported at 1.95 Å resolution. Although the structure displays overall similarities to those of other Snf2 family members, a new structural module was found to be specific to the Fun30 subfamily. Fun30 ATPase-C was shown be monomeric in solution and showed no detectable affinity for dsDNA.

scholarly journals Bacteria “Read” Light To Gain a Competitive Advantage

2019 ◽  
Vol 201 (10) ◽  
Author(s):  
Carolyn E. Lubner
Keyword(s):  
Dna Repair ◽  
Gene Regulation ◽  
Diurnal Cycle ◽  
Regulatory Networks ◽  
Solar Irradiation ◽  
Chemical Bonds ◽  
Repair Gene ◽  
Primary Mechanism ◽  
Dna Repair Gene ◽  
Biological Organisms

ABSTRACT Photosynthesis, the process of converting solar energy into stored chemical bonds, represents the primary mechanism by which biological organisms utilize photons. Light can also be used to activate a number of photosensory compounds and proteins designed to carry out tasks, such as DNA repair, gene regulation, and synchronization with the diurnal cycle. Given that sunlight is incident upon many environments, it is not farfetched to think that life may have evolved other as-yet-undetected mechanisms to profit from solar irradiation. In this issue, Maresca and coworkers detail their observations of light-enhanced growth of several nonphotosynthetic actinobacteria, as well as describe the potential photosensitizer responsible for this phenotype and discuss the regulatory networks involved (J. A. Maresca, J. L. Keffer, P. P. Hempel, S. W. Polson, et al., J Bacteriol 201:e00740-18, 2019, https://doi.org/10.1128/JB.00740-18). This study opens the door to many intriguing questions about the use of light as information in nonphotosynthetic biological systems.

scholarly journals The acetyltransferase Eco1 elicits cohesin dimerization during S phase

2020 ◽  
Author(s):  
Di Shi ◽  
Shuaijun Zhao ◽  
Mei-Qing Zuo ◽  
Jingjing Zhang ◽  
Wenya Hou ◽  
...  
Keyword(s):  
Dna Replication ◽  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
S Phase ◽  
Repair Gene ◽  
Additional Layer ◽  
Ring Model ◽  
Dna Repair Gene ◽  
Chromatid Cohesion

AbstractSister chromatid cohesion is established by Eco1 in S phase. Nevertheless, the exact consequence of Eco1-catalyzed acetylation is unknown, and the cohesive state remains highly controversial. Here we show that self-interactions of cohesin subunits Scc1/Rad21 and Scc3 occur in a DNA replication-coupled manner in both yeast and human. Through cross-linking mass spectrometry and VivosX analysis of purified cohesin, we show that a subpopulation of cohesin may exist as dimers. Importantly, cohesin-cohesin interaction becomes significantly compromised when Eco1 is depleted. On the other hand, deleting either deacetylase Hos1 or Eco1 antagonist Wpl1/Rad61 results in an increase (e.g., from ∼20% to 40%) of cohesin dimers. These findings suggest that cohesin dimerization is controlled by common mechanisms as the cohesion cycle, thus providing an additional layer of regulation for cohesin to execute various functions such as sister chromatid cohesion, DNA repair, gene expression, chromatin looping and high-order organization.Author SummaryCohesin is a ring that tethers sister chromatids since their synthesis during S phase till their separation in anaphase. According to the single-ring model, one ring holds twin sisters. Here we show a conserved cohesin-cohesin interaction from yeast to human. A subpopulation of cohesin is dimerized concomitantly with DNA replication. Cohesin dimerization is dependent on the acetyltransferase Eco1 and counteracted by the anti-establishment factor Wpl1 and deacetylase Hos1. Approximately 20% of cellular cohesin complexes are measured to be dimers, close to the level of Smc3 acetylation by Eco1 in vivo. These findings provide evidence to support the double-ring model in sister chromatid cohesion.

scholarly journals DNA Repair Gene Polymorphism and the Risk of Mitral Chordae Tendineae Rupture

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Aysel Kalayci Yigin ◽  
Mehmet Bulent Vatan ◽  
Ramazan Akdemir ◽  
Muhammed Necati Murat Aksoy ◽  
Mehmet Akif Cakar ◽  
...  
Keyword(s):  
Dna Repair ◽  
Fragment Length Polymorphism ◽  
Control Group ◽  
Chordae Tendineae ◽  
Repair Gene ◽  
Repair Capacity ◽  
Dna Repair Capacity ◽  
Dna Repair Gene ◽  
Increased Risk ◽  
Polymerase Chain

Polymorphisms in Lys939Gln XPC gene may diminish DNA repair capacity, eventually increasing the risk of carcinogenesis. The aim of the present study was to evaluate the significance of polymorphism Lys939Gln in XPC gene in patients with mitral chordae tendinea rupture (MCTR). Twenty-one patients with MCTR and thirty-seven age and sex matched controls were enrolled in the study. Genotyping of XPC gene Lys939Gln polymorphism was carried out using polymerase chain reaction- (PCR-) restriction fragment length polymorphism (RFLP). The frequencies of the heterozygote genotype (Lys/Gln-AC) and homozygote genotype (Gln/Gln-CC) were significantly different in MCTR as compared to control group, respectively (52.4% versus 43.2%,p=0.049; 38.15% versus 16.2%,p=0.018). Homozygote variant (Gln/Gln) genotype was significantly associated with increased risk of MCTR (OR = 2.059; 95% CI: 1.097–3.863;p=0.018). Heterozygote variant (Lys/Gln) genotype was also highly significantly associated with increased risk of MCTR (OR = 1.489; 95% CI: 1.041–2.129;p=0.049). The variant allele C was found to be significantly associated with MCTR (OR = 1.481; 95% CI: 1.101–1.992;p=0.011). This study has demonstrated the association of XPC gene Lys939Gln polymorphism with MCTR, which is significantly associated with increased risk of MCTR.

scholarly journals The Large Subunit of Replication Factor C (Rfclp/Cdc44p) Is Required for DNA Replication and DNA Repair in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Michael A McAlear ◽  
K Michelle Tuffo ◽  
Connie Holm
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Dna Replication ◽  
Uv Radiation ◽  
Large Subunit ◽  
Restrictive Temperature ◽  
Replication Factor C ◽  
Replication Factor ◽  
Factor C

We used genetic and biochemical techniques to characterize the phenotypes associated with mutations affecting the large subunit of replication factor C (Cdc44p or Rfc1p) in Saccharomyces cerevisiae. We demonstrate that Cdc44p is required for both DNA replication and DNA repair in vivo. Cold-sensitive cdc44 mutants experience a delay in traversing S phase at the restrictive temperature following alpha factor arrest; although mutant cells eventually accumulate with a G2/M DNA content, they undergo a cell cycle arrest and initiate neither mitosis nor a new round of DNA synthesis. cdc44 mutants also exhibit an elevated level of spontaneous mutation, and they are sensitive both to the DNA damaging agent methylmethane sulfonate and to exposure to UV radiation. After exposure to UV radiation, cdc44 mutants at the restrictive temperature contain higher levels of single-stranded DNA breaks than do wild-type cells. This observation is consistent with the hypothesis that Cdc44p is involved in repairing gaps in the DNA after the excision of damaged bases. Thus, Cdc44p plays an important role in both DNA replication and DNA repair in vivo.

scholarly journals DNA Repair Gene Polymorphisms and Susceptibility to Urothelial Carcinoma in a Southeastern European Population

2021 ◽  
Vol 28 (3) ◽  
pp. 1879-1885
Author(s):  
Maria Samara ◽  
Maria Papathanassiou ◽  
Lampros Mitrakas ◽  
George Koukoulis ◽  
Panagiotis J. Vlachostergios ◽  
...  
Keyword(s):  
Dna Repair ◽  
Urothelial Carcinoma ◽  
European Population ◽  
Nucleotide Polymorphisms ◽  
Environmental Carcinogens ◽  
Repair Gene ◽  
High Exposure ◽  
Dna Repair Gene ◽  
Increased Risk ◽  
Xrcc3 Thr241met

Single nucleotide polymorphisms (SNPs) in DNA repair genes may predispose to urothelial carcinoma of the bladder (UCB). This study focused on three specific SNPs in a population with high exposure to environmental carcinogens including tobacco and alcohol. A case-control study design was used to assess for presence of XPC PAT +/−, XRCC3 Thr241Met, and ERCC2 Lys751Gln DNA repair gene SNPs in peripheral blood from patients with UCB and healthy individuals. One hundred patients and equal number of healthy subjects were enrolled. The XPC PAT +/+ genotype was associated with a 2-fold increased risk of UCB (OR = 2.16; 95%CI: 1.14–4; p = 0.01). The −/+ and +/+ XPC PAT genotypes were more frequently present in patients with multiple versus single tumors (p = 0.01). No association was detected between ERCC2 Lys751Gln genotypes/alleles, and risk for developing UCB. Presence of the XRCC3 TT genotype (OR = 0.14; 95%CI:0.07–0.25; p < 0.01) and of the T allele overall (OR = 0.26; 95%CI:0.16–0.41; p < 0.01) conferred a protective effect against developing UCB. The XPC PAT −/+ and XRCC3 Thr241Met SNPs are associated with predisposition to UCB. The XPC PAT −/+ SNP is also an indicator of bladder tumor multiplicity, which might require a more individualized surveillance and treatment.

Patients with Systemic Sclerosis Present Increased DNA Damage Differentially Associated with DNA Repair Gene Polymorphisms

2014 ◽  
Vol 41 (3) ◽  
pp. 458-465 ◽  
Author(s):  
Gustavo Martelli Palomino ◽  
Carmen L. Bassi ◽  
Isabela J. Wastowski ◽  
Danilo J. Xavier ◽  
Yara M. Lucisano-Valim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Systemic Sclerosis ◽  
Blood Cells ◽  
Gene Polymorphisms ◽  
Peripheral Blood Cells ◽  
Dna Repair Genes ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Repair Genes

Objective.Patients with systemic sclerosis (SSc) exhibit increased toxicity when exposed to genotoxic agents. In our study, we evaluated DNA damage and polymorphic sites in 2 DNA repair genes (XRCC1Arg399Gln andXRCC4Ile401Thr) in patients with SSc.Methods.A total of 177 patients were studied for DNA repair gene polymorphisms. Fifty-six of them were also evaluated for DNA damage in peripheral blood cells using the comet assay.Results.Compared to controls, the patients as a whole or stratified into major clinical variants (limited or diffuse skin involvement), irrespective of the underlying treatment schedule, exhibited increased DNA damage.XRCC1(rs: 25487) andXRCC4(rs: 28360135) allele and genotype frequencies observed in patients with SSc were not significantly different from those observed in controls; however, theXRCC1Arg399Gln allele was associated with increased DNA damage only in healthy controls and theXRCC4Ile401Thr allele was associated with increased DNA damage in both patients and controls. Further, theXRCC1Arg399Gln allele was associated with the presence of antinuclear antibody and anticentromere antibody. No association was observed between these DNA repair gene polymorphic sites and clinical features of patients with SSc.Conclusion.These results corroborate the presence of genomic instability in SSc peripheral blood cells, as evaluated by increased DNA damage, and show that polymorphic sites of theXRCC1andXRCC4DNA repair genes may differentially influence DNA damage and the development of autoantibodies.

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