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Pho2 dependence in the phosphate signal transduction pathway of Saccharomyces cerevisiae and Candida glabrata

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Description: Comparative genomic analyses of Candida glabrata and Saccharomyces cerevisiae suggest many signal transduction pathways are highly conserved. This study examines the phosphate signal transduction (PHO) pathway of C. glabrata . I demonstrate that components of the pathway are conserved, and confirm the role of CgPHO81, CgPHO80, CgPHO4, CgPHO2 , and CgMSN5 in the PHO pathway by deleting these genes and assaying transcriptional induction of genes homologous to phosphate-regulated S. cerevisiae genes. Unlike S. cerevisiae, C. glabrata shows little dependence on the transcription factor, Pho2, for induction of phosphateregulated genes during phosphate limitation. We demonstrate that the Cg Pho4 protein is sufficient for Pho2-independent gene expression. This study demonstrates that evolutionary changes in phosphate-regulated gene expression occur through alterations in the transcription factor (Pho4) as opposed to cis -regulatory region changes (the promoter).
Language: English
Format: Degree Work