Project description:Carbendazim (Methyl benzimidazol-2-ylcarbamate; MBC) is an antimitotic drug used for broad-spectrum fungicide, antineoplastic and mutagen in microbial breeding. Using a customized SNP microarray technology, this work revealed the effect of MBC on genomic instability (loss of heterozygosity, chromosomal rearrangements and aneuploidy) in the diploid yeast Saccharomyces cerevisiae JSC25.
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genomic instability. In this study, heat-shock-induced genomic alterations were explored in the heterozygous diploid yeast strain JSC25-1. In combination of the whole-genome microarray, the patterns of chromosomal instability induced by heat shock could also be explored at a whole genome level. Using this system, we found heat-shock treatment resulted in hundreds-fold higher rate of genomic alterations, including aneuploidy and loss of heterozygosity (LOH).
Project description:DNA replication stress (DRS)-linked genomic instability has emerged as an important factor driving cancer development. To understand the mechanisms of DRS-associated genomic instability and phenotypic evolution, we mapped chromosomal alterations in a yeast strain with lowered expression of the replicative DNA polymerase δ. At a whole-genome level, we identified both hotspots of mitotic recombination and chromosome-specific aneuploidy dependent on decreased levels of DNA polymerase δ. The high rate of chromosome loss is likely a reflection of reduced DNA repair capacity in strains with low levels of DNA polymerase. Most recombinogenic DNA lesions were introduced during S or G2 phase, presumably as a consequence of broken replication forks.
Project description:Furfural is a key inhibitor in S. cerevisiae fermentation causing serious economic loss. To understand the toxic mechanisms of furfural-induced genomic instability and phenotypic evolution, we mapped chromosomal alterations in 21 furfural-treated yeast strains by whole genome SNP microarrays at a resolution about 1kb.
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying physiological and pharmacological action of small-molecular drugs. Here, a heterozygous diploid S. cerevisiae strain QSS4 was generated to determine whether drugs could induce chromosomal instability by determining the frequency of mitotic recombination. In combination of a custom SNP microarray, the patterns of chromosomal instability induced by drugs could also be explored at a whole genome level in QSS4. Using this system, we found Zeocin (a member of bleomycin family) treatment resulted in hundreds-fold higher rate of genomic alterations, including aneuploidy, loss of heterozygosity (LOH), and chromosomal rearrangement.
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genome instability. Here, a heterozygous diploid S. cerevisiae strain DZP2 was generated to determine the genomic alterations induced by DNA polymerase ε. The expression of POL2 was regulated by the GAL1 promoter. In combination of a custom SNP microarray, the patterns of chromosomal instability induced by low Pol ε could be explored at a whole genome level in DZP2. Using this system, we found hundreds-fold higher rate of genomic alterations, including aneuploidy, loss of heterozygosity (LOH), and chromosomal rearrangement. DNA polymerase ε (Pol ε) is one of the three replicative eukaryotic DNA polymerases. Pol ε deficiency leads to genomic instability and multiple human diseases. Here, we explored global genomic alterations in yeast strains with reduced expression of POL2, the gene that encodes the catalytic subunit of Pol ε. Using whole-genome SNP microarray and sequencing, we found that low levels of Pol ε elevated the rates of mitotic recombination and chromosomal aneuploidy by two orders of magnitude. Strikingly, low levels of Pol ε resulted in a contraction of the number of repeats in the rDNA cluster and reduced the length of telomeres. These short telomeres led to an elevated frequency of break-induced replication, resulting in terminal loss of heterozygosity. In addition, low levels of Pol ε increased the rate of single-base mutations by 13-fold by a Pol ζ-dependent pathway. Finally, the patterns of genomic alterations caused by low levels of Pol ε were different from those observed in strains with low levels of the other replicative DNA polymerases Pol α and Pol δ, providing further insights into the different roles of the B-family DNA polymerases in maintaining genomic stability.
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genome instability. Here, a heterozygous diploid S. cerevisiae strain DZP2 was generated to determine the genomic alterations induced by DNA polymerase ε. The expression of POL2 was regulated by the GAL1 promoter. In combination of a custom SNP microarray, the patterns of chromosomal instability induced by low Pol ε could be explored at a whole genome level in DZP2. Using this system, we found hundreds-fold higher rate of genomic alterations, including aneuploidy, loss of heterozygosity (LOH), and chromosomal rearrangement. DNA polymerase ε (Pol ε) is one of the three replicative eukaryotic DNA polymerases. Pol ε deficiency leads to genomic instability and multiple human diseases. Here, we explored global genomic alterations in yeast strains with reduced expression of POL2, the gene that encodes the catalytic subunit of Pol ε. Using whole-genome SNP microarray and sequencing, we found that low levels of Pol ε elevated the rates of mitotic recombination and chromosomal aneuploidy by two orders of magnitude. Strikingly, low levels of Pol ε resulted in a contraction of the number of repeats in the rDNA cluster and reduced the length of telomeres. These short telomeres led to an elevated frequency of break-induced replication, resulting in terminal loss of heterozygosity. In addition, low levels of Pol ε increased the rate of single-base mutations by 13-fold by a Pol ζ-dependent pathway. Finally, the patterns of genomic alterations caused by low levels of Pol ε were different from those observed in strains with low levels of the other replicative DNA polymerases Pol α and Pol δ, providing further insights into the different roles of the B-family DNA polymerases in maintaining genomic stability.