Often changes in gene expression levels have been considered significant only when above/ below some arbitrarily chosen threshold. We investigated the effect of applying a purely statistical approach to microarray analysis and demonstrated that small changes in gene expression have biological significance. Whole genome microarray analysis of a pde2Delta mutant, constructed in the Saccharomyces cerevisiae reference strain FY23, revealed altered expression of similar to 11% of protein encoding genes. The mutant, characterized by constitutive activation of the Ras/ cAMP pathway, has increased sensitivity to stress, reduced ability to assimilate nonfermentable carbon sources, and some cell wall integrity defects. Applying the Munich Information Centre for Protein Sequences ( MIPS) functional categories revealed increased expression of genes related to ribosome biogenesis and downregulation of genes in the cell rescue, defense, cell death and aging category, suggesting a decreased response to stress conditions. A reduced level of gene expression in the unfolded protein response pathway ( UPR) was observed. Cell wall genes whose expression was affected by this mutation were also identified. Several of the cAMP- responsive orphan genes, upon further investigation, revealed cell wall functions; others had previously unidentified phenotypes assigned to them. This investigation provides a statistical global transcriptome analysis of the cellular response to constitutive activation of the Ras/ cAMP pathway.
Transcriptome profiling of a Saccharomyces cerevisiae mutant with a constitutively activated Ras/cAMP pathway / D.L. Jones, J. Petty, D.C. Hoyle, A. Hayes, E. Ragni, L. Popolo, S.G. Oliver, L.I. Stateva. - In: PHYSIOLOGICAL GENOMICS. - ISSN 1094-8341. - 16:1(2003 Oct 21), pp. 107-118.
Transcriptome profiling of a Saccharomyces cerevisiae mutant with a constitutively activated Ras/cAMP pathway
E. Ragni;L. Popolo;
2003
Abstract
Often changes in gene expression levels have been considered significant only when above/ below some arbitrarily chosen threshold. We investigated the effect of applying a purely statistical approach to microarray analysis and demonstrated that small changes in gene expression have biological significance. Whole genome microarray analysis of a pde2Delta mutant, constructed in the Saccharomyces cerevisiae reference strain FY23, revealed altered expression of similar to 11% of protein encoding genes. The mutant, characterized by constitutive activation of the Ras/ cAMP pathway, has increased sensitivity to stress, reduced ability to assimilate nonfermentable carbon sources, and some cell wall integrity defects. Applying the Munich Information Centre for Protein Sequences ( MIPS) functional categories revealed increased expression of genes related to ribosome biogenesis and downregulation of genes in the cell rescue, defense, cell death and aging category, suggesting a decreased response to stress conditions. A reduced level of gene expression in the unfolded protein response pathway ( UPR) was observed. Cell wall genes whose expression was affected by this mutation were also identified. Several of the cAMP- responsive orphan genes, upon further investigation, revealed cell wall functions; others had previously unidentified phenotypes assigned to them. This investigation provides a statistical global transcriptome analysis of the cellular response to constitutive activation of the Ras/ cAMP pathway.Pubblicazioni consigliate
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