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
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Creator |
BHAT, PJ
VENKATESH, KV |
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Subject |
galregulatory network
molecular noise epigenetic factors enzyme adaptation steady state response |
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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.
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Publisher |
Elsevier
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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 |
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Type |
Article
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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 |
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Language |
en
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