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Stochastic variation in the concentration of a repressor activates GAL genetic switch: implications in evolution of regulatory network

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Title Stochastic variation in the concentration of a repressor activates GAL genetic switch: implications in evolution of regulatory network
 
Creator BHAT, PJ
VENKATESH, KV
 
Subject galregulatory network
molecular noise
epigenetic factors
enzyme adaptation
steady state response
 
Description In Saccharomyces cerevisiae, a recessive mutation in the signal transducer encoded by GAL3 leads to a significant lag in the induction of GAL genes, referred to as long term adaptation phenotype (LTA). Further, gal3 mutation in combination with other genetic defects leads to the non-inducibility of GAL genes. It was shown that the expression of GAL1 encoded galactokinase, a redundant GAL3 like signal transducer, eventually substitutes for the lack of GAL3 signal transduction function. However, how GAL1 gets induced in the absence of GAL3 is not clear. We hypothesize that GAL1 induction in gal3 cells exposed to galactose is due to a stochastic decrease in the repressor, Gal80p concentration, leading to heterogeneity in the population. This observation explains not only LTA observed in gal3 cells but also explains the non-inducibility of gal3 mutants in combination with other genetic defects. By recruiting a dedicated signal transducer, GAL3, S. cerevisiae GAL switch has evolved to overcome the fortuitous induction, which occurs due to low signal to noise ratio in certain mutants of Escherichia coli and Kluveromyces lactis.
 
Publisher Elsevier
 
Date 2009-03-09T07:45:39Z
2011-11-25T18:54:42Z
2011-12-26T13:07:00Z
2011-12-27T05:54:58Z
2009-03-09T07:45:39Z
2011-11-25T18:54:42Z
2011-12-26T13:07:00Z
2011-12-27T05:54:58Z
2005
 
Type Article
 
Identifier FEBS Letters 579(3), 597-603
0014-5793
http://dx.doi.org/10.1016/j.febslet.2004.12.038
http://hdl.handle.net/10054/912
http://dspace.library.iitb.ac.in/xmlui/handle/10054/912
 
Language en