Wei Cheng

Defense Date

6-25-2004

Graduation Date

Summer 2004

Availability

Immediate Access

Submission Type

thesis

Degree Name

MS

Department

Biological Sciences

Committee Chair

Jana Patton-Vogt

Committee Member

David J. Lampe

Committee Member

Edward Weisberg

Keywords

GIT1, Inositol and Phosphate, Regulation, S. cerevisiae, Transcription

Abstract

Glycerophosphoinositol is produced through deacylation of the essential phospholipid phosphatidylinositol. In Saccharomyces cerevisiae, when inositol is limiting in the extracellular environment, the glycerophosphoinositol can be transported into the cell through the permease encoded by GIT1 . In this study, Northern blotting and GIT1 promoter activity were analyzed to assess the nutritional factors responsible for the regulation of GIT1 transcription. Here, I report that GIT1 transcript levels are greater in cells starved for phosphate, with or without inositol limitation, than in cells only limited for inositol. Ino2p and Ino4p are required for full GIT1 expression when the medium lacks both inositol and phosphate. Pho2p and Pho4p are required for GIT1 expression under all growth conditions tested. A 300 base pair region of the GIT1 promoter containing potential Pho4p binding sites is shown to be required for full GIT1 expression. Phd1p and Sok2p do not appear to be involved in the transcriptional regulation of GIT1 in response to inositol and phosphate limitation. Finally, my study revealed that glycerophosphoinositol can act as the cell's sole source of phosphate.

Format

PDF

Language

English

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