UV-Induction of Thymine-Containing Dimers in Saccharomyces cerevisiae

Abstract

In haploid and diploid S. cerevisiae the dimer yield ratio TT̂/CT̂ is found to be 1.2/1 and 1.3/1, resp., at the UV (254 nm) unit dose 1 erg/mm2, the share of TT̂ and CT̂ in a UV (254 nm) lethal hit being 0.7 TT̂ and 0.6 CT̂. A general formulation of the UV lethal hit is given and discussed. The TT̂ + CT̂ yields obtained for S. cerevisiae are compared to those reported for other organisms. It is found that there obviously exists a directly proportional linear correlation between genome size and TT̂ + CT̂ yield for the UV dose range well below the stationary levels of the TT̂ and CT̂ formation kinetics.

In vivo and in silico analysis of PCNA ubiquitylation in the activation of the Post Replication Repair pathway in S. cerevisiae

“…The number of DNA lesions (CPD plus 6-4 PP) generated on the genome after different UV dose expositions was determined by using literature data [65,66]. These measurements, reported in Table 4, were exploited to derive the linear regression equations required to estimate the correlation between the radiation doses used in our laboratory experiments, and the corresponding number of lesions induced on S. cerevisiae genome.…”

“…In particular, we derived the equations y =200.248 x and y =222.22 x , by using data reported in [65,66], respectively (where y is the number of genomic lesions induced by the UV dose x ). Afterwards, a χ 2 cross-validation test was applied over the two datasets.…”

“…Afterwards, a χ 2 cross-validation test was applied over the two datasets. The result of the cross-validation indicated that the best coefficient is the one related to the data reported in [65], being χ 2 = 0.049 for the dataset from [65] and χ 2 = 129.79 for the dataset from [66]. Therefore, the first equation was applied to estimate the number of genomic lesions induced by the various UV doses considered in our laboratory experiments.…”