RESUMO
The functions of many open reading frames (ORFs) identified in genome-sequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.
Assuntos
Deleção de Genes , Genes Essenciais , Genoma Fúngico , Fases de Leitura Aberta , Saccharomyces cerevisiae/genética , Meios de Cultura , Regulação Fúngica da Expressão Gênica , Marcação de Genes , Genes Fúngicos , Fenótipo , Reação em Cadeia da Polimerase , Recombinação Genética , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
The variety of environmental stresses is probably the major challenge imposed on transcription activators and the transcriptional machinery. To precisely describe the very early genomic response developed by yeast to accommodate a chemical stress, we performed time course analyses of the modifications of the yeast gene expression program which immediately follows the addition of the antimitotic drug benomyl. Similar analyses were conducted with different isogenic yeast strains in which genes coding for relevant transcription factors were deleted and coupled with efficient bioinformatics tools. Yap1 and Pdr1, two well-known key mediators of stress tolerance, appeared to be responsible for the very rapid establishment of a transient transcriptional response encompassing 119 genes. Yap1, which plays a predominant role in this response, binds, in vivo, promoters of genes which are not automatically up-regulated. We proposed that Yap1 nuclear localization and DNA binding are necessary but not sufficient to elicit the specificity of the chemical stress response.
Assuntos
Benomilo/farmacologia , Proteínas de Ligação a DNA/fisiologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/genética , Transativadores/fisiologia , Fatores de Transcrição/fisiologia , Proteínas de Ligação a DNA/genética , Regulação para Baixo/fisiologia , Perfilação da Expressão Gênica , Genoma Fúngico , Análise de Sequência com Séries de Oligonucleotídeos , Saccharomyces cerevisiae/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/genética , Deleção de Sequência/genética , Estimulação Química , Transativadores/genética , Fatores de Transcrição/genética , Regulação para Cima/fisiologiaRESUMO
In order to distinguish chilling and freezing tolerance mechanisms in pea, responses to cold exposure were compared between the freezing tolerant line Champagne and the sensitive line Terese. Global gene expression was considered in the two lines and associated with morphological, histological and biochemical approaches. The chilling tolerance in both lines was related to responses of the CBF, COR and LEA genes belonging to the CBF regulon, with greater earliness of expression in the Champagne genotype. The freezing tolerance, only observed in Champagne, was associated with acclimation processes such as cellular osmotic stabilization, photosynthesis modifications, antioxidants production, modifications in hormone metabolism, cell wall composition and dynamics.
Assuntos
Aclimatação/genética , Temperatura Baixa , Genes de Plantas , Pisum sativum/metabolismo , Proteínas de Plantas/metabolismo , Regulon , Transcriptoma , Congelamento , Genótipo , Pisum sativum/genética , Proteínas de Plantas/genéticaRESUMO
In the framework of the European Network for Functional Analysis (EUROFAN), five packages of 96 ORFs from chromosomes III, IV, VII, XIII, XIV and XV were subjected to systematic deletions in an isogenic derivative of strain S288c. Deletions were constructed in diploid and haploid strains. Two questionable ORFs overlapping with larger ORFs and seven TY ORFs were discarded. A total of 456 heterozygous and 385 homozygous deletant diploids were obtained. Sixty-nine deletions, 25 of which had never been published before, were lethal in haploid strains and 30 caused slow cellular growth.