help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published July 28, 2006. doi:10.1529/biophysj.105.077420
© 2006 by the Biophysical Society.

A more recent version of this article appeared on October 15, 2006.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow supplemental
Right arrow All Versions of this Article:
biophysj.105.077420v1
91/8/2833    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by van Hoek, M.
Right arrow Articles by Hogeweg, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by van Hoek, M.
Right arrow Articles by Hogeweg, P.

BIOPHYSICAL THEORY AND MODELING

In silico evolved lac operons exhibit bistability for artificial inducers, but not for lactose

Milan van Hoek 1* and Paulien Hogeweg 1

1 Utrecht University

* To whom correspondence should be addressed. E-mail: m.j.a.vanhoek{at}bio.uu.nl.

Submitted on November 8, 2005
Revised on January 31, 2006
Accepted on 11 July 2006


  Abstract
Bistability in the lac operon of Escherichia coli has been widely studied, both experimentally and theoretically. Experimentally, bistability has been observed when Escherichia coli is induced by an artificial, non-metabolizable, inducer. However, if the lac operon is induced with lactose, the natural inducer, bistability has not been demonstrated. We derive an analytical expression which can predict the occurrence of bistability both for artificial inducers and lactose. We find very different conditions for bistability in the two cases. Indeed, for artificial inducers bistability is predicted, but for lactose the condition for bistability is much more difficult to satisfy. Moreover we demonstrate that in silico evolution of the lac operon generates an operon that avoids bistability with respect to lactose, but does exhibit bistability with respect to artificial inducers. Indeed the activity of this evolved operon strikingly resembles the experimentally observed activity of the operon. Thus our computational experiments suggest that the wild-type lac operon, which regulates lactose metabolism, is not a bistable switch. Nevertheless, for engineering purposes, this operon can be used as a bistable switch with artificial inducers.

Key Words: analytical model, computational model, evolution, gene regulation, genetic switch, hysteresis




This article has been cited by other articles:


Home page
 Biophys. JHome page
M. Santillan
Bistable Behavior in a Model of the lac Operon in Escherichia coli with Variable Growth Rate
Biophys. J., March 15, 2008; 94(6): 2065 - 2081.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
M. Santillan, M. C. Mackey, and E. S. Zeron
Origin of Bistability in the lac Operon
Biophys. J., June 1, 2007; 92(11): 3830 - 3842.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2006 by the Biophysical Society.