Go to  Advanced Search

GAL4 is regulated by a glucose-responsive functional domain

Show full item record

Files in this item

Files Size Format Description   View
ubc_1992_fall_stone_geoffrey.pdf 2.372Mb Adobe Portable Document Format   View/Open
Title: GAL4 is regulated by a glucose-responsive functional domain
Author: Stone, Geoffrey
Degree: Master of Science - MSc
Program: Biochemistry and Molecular Biology
Copyright Date: 1992
Issue Date: 2008-12-18
Series/Report no. UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/]
Abstract: Gene regulation in eukaryotes has been a major focus of molecular biological research, aiming to elucidate the genetic processes involved in cell development and disease. To better understand the fundamentals of gene regulation, simple cellular systems such as lower eukaryotes are being studied. These systems are easier to analyze through genetic mutation, providing an overall picture of a particular genetic pathway. One such system is the galactose utilization (GAL) pathway of the yeast Saccharomyces cerevisiae. Expression of the GAL genes is determined by the availability of carbon sources in the media. This regulation is exercised through GAL4, a transcriptional activator of the GAL genes. The availability of galactose induces GAL4 activity by inhibiting the GAL4 negative regulator, GAL80. Glucose, the preferred carbon source, inhibits GAL4 activity by several mechanisms. I demonstrate that one mechanism of glucose repression is mediated by a large, previously uncharacterized, central region of GAL4. This region directly inhibits GAL4 activity in the presence of glucose; deletion of the central region eliminates glucose repression. Fusion of the central region to a heterologous transcriptional activator (LexA-VP16) confers glucose repression. Inhibitory domains in the central region constitutively inhibit activity when a region called the glucose response domain, also present in the central region, is deleted. Inhibition of LexA-VP16 by the central region is accompanied by loss of DNA binding. I suggest that direct inhibition of GAL4 activity in glucose is mediated by interaction of the central region inhibitory domains with the DNA binding and dimerization domain, an interaction which prevents DNA binding. In the absence of glucose, DNA binding is restored by interaction of the glucose response domain with the inhibitory domains.
Affiliation: Medicine, Faculty of
URI: http://hdl.handle.net/2429/3099
Scholarly Level: Graduate

This item appears in the following Collection(s)

Show full item record

UBC Library
1961 East Mall
Vancouver, B.C.
Canada V6T 1Z1
Tel: 604-822-6375
Fax: 604-822-3893