Open AccessGAL regulon of S accharomyces cerevisiae performs optimally to maximize growth on galactose
Author(s) -
Malakar Pushkar,
Venkatesh Kareenhalli V.
Publication year - 2014
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/1567-1364.12109
Subject(s) - regulon , saccharomyces cerevisiae , galactose , biology , repressor , mutant , biochemistry , genetics , gene , gene expression
The GAL regulon in S accharomyces cerevisiae is a well‐characterized genetic network that is utilized for the metabolism of galactose as an energy source. The network contains a transcriptional activator, G al4p, which binds to its cognate‐binding site to express GAL genes. Further, G al80p and G al3p are the repressor and galactose sensor, respectively, which are also under the regulation of GAL regulon. It is shown that the wild‐type strain produces only about 80% of the maximum expression feasible from the regulon, which is observed in a mutant strain lacking G al80p. This raises a fundamental question regarding the optimality of expression from the GAL regulon in S . cerevisiae . To address this issue, we evaluated the burden on growth due to the synthesis of GAL proteins in S . cerevisiae . The analysis demonstrated that both the media type and the extent of enzyme synthesized play a role in determining the burden on growth. We show that the burden can be quantified by relating to a parameter, β, the ratio of enzyme activity to the initial substrate concentration. The analysis demonstrated that the GAL regulon of the wild‐type strain performed effectively to optimize growth on galactose.