Design and construction of a versatile synthetic network for bistable gene expression in mammalian systems

J Comput Biol. 2011 Feb;18(2):195-203. doi: 10.1089/cmb.2010.0208.


We constructed and modeled a novel synthetic network which may be able to exhibit bistable expression of a reporter gene in mammalian cells. This network is based on an aptamer-fused short-hairpin RNA (shRNA) directed against a single mRNA encoding both a EGFP reporter gene and the repressor tTR-KRAB, which, in turn, represses transcription of the shRNA. The activity of the shRNA can be controlled by an inducer molecule (theophylline) which prevents the aptamer-fused shRNA to be properly processed. Repression of the tTR-KRAB can be relieved by treatment with doxycyline. This reciprocal negative feed-back loop can exhibit a bistable response, as shown through the mathematical analysis performed here. Specifically, the network can be controlled to induce sustained expression of a shRNA, or the reporter gene, with a transient input of two different inducer molecules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aptamers, Nucleotide / genetics
  • CHO Cells
  • Computational Biology / methods*
  • Cricetinae
  • Cricetulus
  • Doxycycline / pharmacology
  • Gene Expression Regulation* / drug effects
  • Gene Regulatory Networks* / drug effects
  • HEK293 Cells
  • Humans
  • Mammals / genetics*
  • Models, Genetic
  • RNA, Small Interfering / metabolism


  • Aptamers, Nucleotide
  • RNA, Small Interfering
  • Doxycycline