Operator Sequence Alters Gene Expression Independently of Transcription Factor Occupancy in Bacteria
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Garcia-2012-Operator Sequence Al.pdf
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Author(s)
Garcia, Hernan G.
Boedicker, James Q.
Osborne, Melisa
Gelles, Jeff
Kondev, Jane
Phillips, Rob
Sanchez Ferro, Alvaro
Date Issued
July 2012
Journal
Cell Reports
Publisher
Elsevier
Citation
Garcia, Hernan G., Alvaro Sanchez, James Q. Boedicker, Melisa Osborne, Jeff Gelles, Jane Kondev, and Rob Phillips. “Operator Sequence Alters Gene Expression Independently of Transcription Factor Occupancy in Bacteria.” Cell Reports 2, no. 1 (July 2012): 150–161.
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Final published version
Abstract
A canonical quantitative view of transcriptional regulation holds that the only role of operator sequence is to set the probability of transcription factor binding, with operator occupancy determining the level of gene expression. In this work, we test this idea by characterizing repression in vivo and the binding of RNA polymerase in vitro in experiments where operators of various sequences were placed either upstream or downstream from the promoter in Escherichia coli. Surprisingly, we find that operators with a weaker binding affinity can yield higher repression levels than stronger operators. Repressor bound to upstream operators modulates promoter escape, and the magnitude of this modulation is not correlated with the repressor-operator binding affinity. This suggests that operator sequences may modulate transcription by altering the nature of the interaction of the bound transcription factor with the transcriptional machinery, implying a new layer of sequence dependence that must be confronted in the quantitative understanding of gene expression.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1016/j.celrep.2012.06.004
