Background Upon contact with agencies that harm DNA, Saccharomyces cerevisiae undergo

Background Upon contact with agencies that harm DNA, Saccharomyces cerevisiae undergo wide-spread reprogramming of gene appearance. replies had been determined between your -rays and enediynes, using the induction of DNA tension Rabbit polyclonal to ZNF10 and fix response genes, as well as the repression of ribosomal biogenesis genes. Despite these common replies, a small fraction of the response induced by gamma rays was repressed with the enediynes and vise versa, recommending the fact that enediyne response isn’t completely “radiomimetic.” Regression analysis identified 55 transcripts with gene expression induction associated both with double- or single-strand break formation. The S. cerevisiae “DNA damage Diethylstilbestrol supplier signature” genes as defined by Gasch et al. [1] were enriched among regulated transcripts associated with single-strand breaks, while genes involved in cell cycle regulation were associated with double-strand breaks. Conclusion Dissection of the transcriptional response in yeast that is specifically signaled by DNA strand breaks has identified that single-strand breaks provide the signal for activation of transcripts encoding proteins involved in the DNA damage signature in S. cerevisiae, and double-strand breaks signal changes in cell cycle regulation genes. Background Exposure to DNA damaging agents can cause mutation and cell death and may ultimately lead to disease. Protection from this damage is provided by a host of DNA repair and cell cycle checkpoint proteins that collectively represent numerous pathways to help in the recovery response [2]. In humans, there are approximately 150 DNA repair and cell cycle checkpoint proteins that serve to ensure the repair of damage caused to DNA [3,4] and most of these have functional homologues in S. cerevisiae. Recently, studies have shown that proteins with additional cellular functions beyond DNA repair and cell cycle regulation may ameliorate the toxic effects of agents that cause DNA damage [5-8]. Genome-wide phenotyping studies to identify genes involved in cellular recovery after exposure to DNA alkylating agents, such as methyl methane sulfonate (MMS), indicate that a vast array of cellular processes are required for the recovery of S. cerevisiae. Transcriptional profiling demonstrated that up to 30% of the S. cerevisiae ~6000 genes respond upon exposure to MMS in a time-, agent- and dose-dependent manner [9,10]. Given this vast transcriptional response to damaging agents like MMS and the knowledge that, in addition to DNA, these agents can also damage proteins, RNA and lipids, we set out to identify the transcriptional response specifically caused by damage to DNA. Here we compared the responses of S. cerevisiae upon exposure to -radiation, a non-selective oxidant that attacks DNA (base and sugar), lipids, carbohydrates, proteins and small metabolites in cells, with the response of S. cerevisiae to a panel of enediyne antibiotics that are known to damage DNA and not other cellular molecules (calicheamicin 1I, esperamicin A1 and neocarzinostatin; structures shown in Diethylstilbestrol supplier Figure ?Figure1)1) [11,12]. The enediyne family is a structurally diverse group of DNA-cleaving molecules that undergo reductive activation, presumably by glutathione in vivo, to form a diradical intermediate that binds with high affinity (109 M-1) in the minor groove of DNA and abstract hydrogen atoms from deoxyribose. This “radiomimetic” damage leads to the formation of well-defined proportions of single- and double-stranded DNA lesions unique to each type of enediyne [11,12] the proportions of which are noted in Table ?Table1.1. With no damage to DNA bases, the enediynes specifically oxidize the deoxyribose moiety to produce either direct strand breaks with various sugar residues or phosphate groups attached to the 3′- or 5′-ends of the breaks, or various unstable oxidized abasic sites [11]. Figure 1 Chemical structures and relative ratios of double-strand to single-strand lesions generated. Three enediynes were used for treatment in S. cerevisiae including calicheamicin 1I, esperamicin A1 and neocarzinostatin. Each of these results in varying … Table 1 Proportions of Single- and Double-Strand Damage Produced by -Radiation and Enediynes Expression profiling experiments have been performed using some of these agents independently [13,14]. However, there are no studies that directly compare the responses of these enediynes to each other and to that of -radiation under identical conditions. We establish four key findings: (i) under conditions of similar cell survival, exposure to nonselective -radiation results in more extensive reprogramming of S. cerevisiae transcription than does exposure to the DNA-selective enediynes; (ii) in response to Diethylstilbestrol supplier DNA-strand breaks induced by both the non-selective and selective treatments, S. cerevisiae induces genes involved in DNA repair and the general stress response and represses genes encoding for ribosomal biogenesis; (iii) a considerable fraction of the response upon exposure to -radiation was not mimicked by treatment with the enediynes; and (iv) the “DNA damage signature” as described by Gasch et al. [1] in S. cerevisiae is.