Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA151217 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Global mapping of ribonucleotides embedded in DNA
| PRJNA261234 | ENA
Project description:Ribonucleotides incorporated by the yeast mitochondrial DNA polymerase are not repaired
| PRJNA391428 | ENA
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genome instability. Here, heterozygous S. cerevisiae zygotes were generated to determine the genomic alterations induced by sudden introduction of active RNase H2. In combination of a custom SNP microarray, the patterns of chromosomal instability could be explored at a whole genome level. Ribonucleotides can be incorporated into DNA during replication by the replicative DNA polymerases. These aberrant DNA subunits are efficiently recognized and removed by Ribonucleotide Excision Repair, which is initiated by the heterotrimeric enzyme RNase H2. While RNase H2 is essential in higher eukaryotes, the yeast Saccharomyces cerevisiae can survive without RNase H2 enzyme, although the genome undergoes mutation, recombination and other genome instability events at an increased rate. Although RNase H2 can be considered as a protector of the genome from the deleterious events that can ensue from recognition and removal of embedded ribonucleotides, under conditions of high ribonucleotide incorporation and retention in the genome in a RNase H2-negative strain, sudden introduction of active RNase H2 causes massive DNA breaks and genome instability in a condition which we term “ribodysgenesis”. The DNA breaks and genome instability arise solely from RNase H2 cleavage directed to the ribonucleotide-containing genome. Survivors of ribodysgenesis have massive loss of heterozygosity events stemming from recombinogenic lesions on the ribonucleotide-containing DNA, with increases of over 1000X from wild-type. DNA breaks are produced over one to two divisions and subsequently cells adapt to RNase H2 and ribonucleotides in the genome and grow with normal levels of genome instability.
2022-03-26 | GSE199262 | GEO
Project description:To investigate nuclear DNA replication enzymology in vivo, we have studied Saccharomyces cerevisiae strains containing a pol2-16 mutation that inactivates the catalytic activities of DNA polymerase δ (Pol δ). Although pol2-16 mutants survive, their spore colonies are very tiny, with increased doubling time, larger than normal cells, aberrant nuclei, and rapid suppressor mutation accumulation. These phenotypes reveal a severe growth defect that is distinct from that of strains that lack Pol δ proofreading (pol2-4), consistent with the idea that Pol δ is the major leading strand replicase. Ribonucleotides are also incorporated into the pol2-16 genome in patterns consistent with leading strand replication by Pol δ when Pol δ is absent. More importantly, ribonucleotide distributions at replication origins suggest that in strains encoding all three replicases, Pol δ contributes to initiation of leading-strand replication. We describe two possible models.
2018-02-27 | GSE101698 | GEO
Project description:H3 ChIP and input DNA were hybridized to Affymetrix GeneChip S. cerevisiae Tiling 1.0R Array Genome-wide mapping of nucleosomes generated by micrococcal nuclease (MNase) suggests that yeast promoter and terminator regions are very depleted of nucleosomes, predominantly because their DNA sequences intrinsically disfavor nucleosome formation. However, MNase has strong DNA sequence specificity that favors cleavage at promoters and terminators and accounts for some of the correlation between occupancy patterns of nucleosomes assembled in vivo and in vitro. Using an improved method for measuring nucleosome occupancy in vivo that does not involve MNase, we confirm that promoter regions are strongly depleted of nucleosomes, but find that terminator regions are much less depleted than expected. Unlike at promoter regions, nucleosome occupancy at terminators is strongly correlated with the orientation of and distance to adjacent genes. In addition, nucleosome occupancy at terminators is strongly affected by growth conditions, indicating that it is not primarily determined by intrinsic histone-DNA interactions. Rapid removal of RNA polymerase II (Pol II) causes increased nucleosome occupancy at terminators, strongly suggesting a transcription-based mechanism of nucleosome depletion. However, the distinct behavior of terminator regions and their corresponding coding regions suggests that nucleosome depletion at terminators is not simply associated with passage of Pol II, but rather involves a distinct mechanism linked to 3’ end formation.
2010-09-21 | GSE23778 | GEO
Project description:Previous work has demonstrated the presence of ribonucleotides in human mitochondrial DNA (mtDNA) and in the present study we use a genome-wide approach to precisely map the location of these. We find that ribonucleotides are distributed evenly between the heavy- and light-strand of mtDNA. The relative levels of incorporated ribonucleotides reflect that DNA polymerase γ discriminates the four ribonucleotides differentially during DNA synthesis. The observed pattern is also dependent on the mitochondrial deoxyribonucleotide (dNTP) pools and disease-causing mutations that change these pools alter both the absolute and relative levels of incorporated ribonucleotides. Our analyses strongly suggest that DNA polymerase γ-dependent incorporation is the main source of ribonucleotides in mtDNA and argues against the existence of a mitochondrial ribonucleotide excision repair pathway in human cells. Furthermore, we clearly demonstrate that when dNTP pools are limiting, ribonucleotides serve as a source of building blocks to maintain DNA replication and genome stability. Increased levels of embedded ribonucleotides in patient cells with disturbed nucleotide pools may constitute to a pathogenic mechanism that affects mtDNA stability and impair new rounds of mtDNA replication
2017-02-13 | GSE90054 | GEO
Project description:Misincorporation of ribonucleotides into DNA during genome replication has recently become recognized as a significant source of genomic instability. The frequency of ribonucleotides in the genome is determined by dNTP/rNTP ratios, the ability of the DNA polymerases to discriminate against ribonucleotides, and by the capacity of repair mechanisms to remove misincorporated ribonucleotides. To simultaneously compare how the nuclear and mitochondrial genomes incorporate and remove ribonucleotides, we challenged these processes by imbalancing cellular dNTP pools. Using a collection of yeast strains with altered dNTP pools, we discovered an inverse relationship between the concentration of individual dNTPs and the amount of the corresponding ribonucleotides incorporated in mitochondrial DNA, while in nuclear DNA the ribonucleotide pattern was only altered in the absence of ribonucleotide excision repair. Our analysis uncovers major differences in ribonucleotide repair between the two genomes and provides concrete evidence that yeast mitochondria lack mechanisms for repair of misincorporated ribonucleotides.
2017-11-07 | GSE100352 | GEO
Project description:Capture and massively parallel DNA sequencing of ribonucleotides embedded in S. cerevisiae genomic DNA We developed a new method to map the positions of ribonucleotides embedded in DNA using the unique specificity of A. thaliana tRNA ligase. Ribonucleotides were generated in budding yeasts of different genetic backgrounds and mapped to single nucleotide resolution using the new method.
2015-01-15 | E-GEOD-61464 | biostudies-arrayexpress