Document Detail

Mode of regulation and the insulation of bacterial gene expression.
MedLine Citation:
PMID:  22633488     Owner:  NLM     Status:  MEDLINE    
A gene can be said to be insulated from environmental variations if its expression level depends only on its cognate inducers, and not on variations in conditions. We tested the insulation of the lac promoter of E. coli and of synthetic constructs in which the transcription factor CRP acts as either an activator or a repressor, by measuring their input function-their expression as a function of inducers-in different growth conditions. We find that the promoter activities show sizable variation across conditions of 10%-100% (SD/mean). When the promoter is bound to its cognate regulator(s), variation across conditions is smaller than when it is unbound. Thus, mode of regulation affects insulation: activators seem to show better insulation at high expression levels, and repressors at low expression levels. This may explain the Savageau demand rule, in which E. coli genes needed often in the natural environment tend to be regulated by activators, and rarely needed genes by repressors. The present approach can be used to study insulation in other genes and organisms.
Vered Sasson; Irit Shachrai; Anat Bren; Erez Dekel; Uri Alon
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular cell     Volume:  46     ISSN:  1097-4164     ISO Abbreviation:  Mol. Cell     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-05-28     Completed Date:  2012-07-27     Revised Date:  2014-02-20    
Medline Journal Info:
Nlm Unique ID:  9802571     Medline TA:  Mol Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  399-407     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Elsevier Inc. All rights reserved.
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MeSH Terms
Cyclic AMP / metabolism
Cyclic AMP Receptor Protein / metabolism
Escherichia coli / genetics*,  metabolism
Escherichia coli Proteins / metabolism
Gene Expression Regulation, Bacterial*
Genes, Bacterial
Genes, Reporter
Lac Operon
Mathematical Concepts
Models, Genetic
Promoter Regions, Genetic
Grant Support
249919//European Research Council
Reg. No./Substance:
0/Cyclic AMP Receptor Protein; 0/Escherichia coli Proteins; 0/crp protein, E coli; E0399OZS9N/Cyclic AMP
Comment In:
Mol Cell. 2012 Jun 8;46(5):551-2   [PMID:  22681881 ]

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