title: A specific transcriptional response of yeast cells to camptothecin dependent on the Swi4 and Mbp1 factors.
abstract: Topoisomerase I (Top1) is the specific target of the anticancer drug camptothecin (CPT) that interferes with enzyme activity promoting Top1-mediated DNA breaks and inhibition of DNA and RNA synthesis. To define the specific transcriptional response to CPT, we have determined the CPT-altered transcription profiles in yeast by using a relatively low concentration of the drug. CPT could alter global expression profiles only if a catalytically active Top1p was expressed in the cell, demonstrating that drug interference with Top1 was the sole trigger of the response. A total of 95 genes showed a statistically-significant alterations. Gene Ontology term analyses suggested that the cell response was mainly to the inhibition of nucleic acid synthesis and cell cycle progression. Promoter sequence analyses of the 22 up-regulated genes and expression studies in gene-deleted strains showed that the transcription factors, Swi4p and Mbp1p, mediate at least partially the transcriptional response to CPT. The MBP1 gene deletion abrogates a transient cell growth delay caused by CPT whereas the SWI4 gene deletion increases yeast resistance to CPT. Thus, the findings show that yeast cells have a highly selective and sensitive transcriptional response to CPT depending on SWI4 and MBP1 genes suggesting a complex regulation of cell cycle progression by the two factors in the presence of CPT.
authors.affiliation: G Moruzzi Department of Biochemistry, University of Bologna, Bologna, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Lotito
authors.forename: Alessandra
authors.initials: A
authors.lastname: Russo
authors.forename: Susana
authors.initials: S
authors.lastname: Bueno
authors.forename: Giovanni
authors.initials: G
authors.lastname: Chillemi
authors.forename: Maria Vittoria
authors.initials: MV
authors.lastname: Fogli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Capranico
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D002166:Camptothecin / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004264:DNA Topoisomerases, Type I; D004268:DNA-Binding Proteins; D015536:Down-Regulation / Q000187:drug effects; D053263:Gene Regulatory Networks / Q000187:drug effects; D005800:Genes, Fungal / Q000235:genetics; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; C083209:MBP1 protein, S cerevisiae; C062214:SWI4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin