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: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:Furfural is a potential mutagenic agent. To explore the global effect of furfural on genomic intergrity, chromosomal alterations in 14 furfural-treated isolates of JSC25-1 strain were determined by whole genome SNP microarrays at a resolution about 1kb. Our results showed furfural exposure results in striking elevations of both mitotic recombination and aneuploidy events in yeast.
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:We developed an artificial genome evolution system, which we termed ‘TAQing’, by introducing multiple genomic DNA double-strand breaks using a heat-activatable endonuclease in mitotic yeast. The heat-activated endonuclease, TaqI, induced random DSBs, which resulted in diverse types of chromosomal rearrangements including translocations. Array comparative genomic hybridization (aCGH) analysis was performed with cell-fused Saccharomyces cerevisiae strains induced genome evolution by TAQing system. Some of copy number variations (CNVs) induced by massive genome rearrangements were detected in the TAQed yeast strains.
Project description:Oxidative stress is a common factor threating genomic stability in almost all aerobic organisms. Using a yeast screening system, we measured the frequency of mitotic recombination was greatly elevated after H2O2 treatment. H2O2 was able to break chromatid directly in G1 synchronized cells and homologous recombination was induced to repair DNA double stand breaks at S/G2 phase. By whole genome SNP microarray and sequencing, the patterns of H2O2 induced loss of heterozygosity (LOH; gene conversion and crossover), chromosomal rearrangement, and aneuploidy changes were revealed. LOH events were the most common genomic alterations induced by H2O2 and were randomly distributed throughout the genome.