DSpace
 

DSpace at IIT Bombay >
IITB Publications >
Article >

Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/4626

Title: Quantitative analysis of GAL genetic switch of Saccharomyces cerevisiae reveals that nucleocytoplasmic shuttling of Gal80p results in a highly sensitive response to galactose
Authors: VERMA, M
BHAT, PJ
VENKATESH, KV
Keywords: transcriptional activator gal4
cyclin-cdk complex
gal4p-activated genes
signal-transduction
glucose repression
dna-binding
yeast
expression
protein
induction
Issue Date: 2003
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Citation: JOURNAL OF BIOLOGICAL CHEMISTRY, 278(49), 48764-48769
Abstract: The nucleocytoplasmic shuttling of the repressor Gal80p is known to play a pivotal role in the signal transduction process of GAL genetic switch of Saccharomyces cerevisiae (Peng, G., and Hopper, J. E. ( 2002) Proc. Natl. Acad. Sci. U. S. A. 99, 8548 - 8553). We have developed a comprehensive model of this GAL switch to quantify the expression from the GAL promoter containing one or two Gal4p-binding sites and to understand the biological significance of the shuttling process. Our experiments show that the expression of proteins from the GAL promoter containing one and two binding sites for Gal4p is ultrasensitive ( a steep response to a given input). Furthermore, the model revealed that the shuttling of Gal80p is the key step in imparting ultrasensitive response to the inducer. During induction, free Gal80p concentration is altered by sequestration, without any change in the distribution coefficient across the nuclear membrane. Furthermore, the estimated concentrations of Gal80p and Gal3p allow basal expression of alpha-galactosidase, but not beta-galactosidase, from the GAL promoter containing one and two binding sites for Gal4p, respectively. Conversely, the expression from genes with two binding sites is more sensitive to inducer concentration as compared with one binding site. We show that autoregulation of Gal80p is coincidental to the autoregulation of Gal3p, and it does not impart ultrasensitivity. We conclude from our analysis that the ultrasensitivity of the GAL genetic switch is solely because of the shuttling phenomena of the repressor Gal80p across the nuclear membrane.
URI: http://dx.doi.org/10.1074/jbc.M303526200
http://dspace.library.iitb.ac.in/xmlui/handle/10054/4626
http://hdl.handle.net/10054/4626
ISSN: 0021-9258
Appears in Collections:Article

Files in This Item:

There are no files associated with this item.

View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback