title: The cumate gene-switch: a system for regulated expression in mammalian cells.
abstract: BACKGROUND
  A number of expression systems have been developed where transgene expression can be regulated. They all have specific characteristics making them more suitable for certain applications than for others. Since some applications require the regulation of several genes, there is a need for a variety of independent yet compatible systems.
  
  
  RESULTS
  We have used the regulatory mechanisms of bacterial operons (cmt and cym) to regulate gene expression in mammalian cells using three different strategies. In the repressor configuration, regulation is mediated by the binding of the repressor (CymR) to the operator site (CuO), placed downstream of a strong constitutive promoter. Addition of cumate, a small molecule, relieves the repression. In the transactivator configuration, a chimaeric transactivator (cTA) protein, formed by the fusion of CymR with the activation domain of VP16, is able to activate transcription when bound to multiple copies of CuO, placed upstream of the CMV minimal promoter. Cumate addition abrogates DNA binding and therefore transactivation by cTA. Finally, an adenoviral library of cTA mutants was screened to identify a reverse cumate activator (rcTA), which activates transcription in the presence rather than the absence of cumate.
  
  
  CONCLUSIONS
  We report the generation of a new versatile inducible expression system.
authors.affiliation: Institut de Recherche en Biotechnologie, Conseil National de Recherches du Canada, 6100 Royalmount Avenue, Montréal, Québec, H4P 2R2, Canada. alaka.mullick@cnrc-nrc.gc.ca
authors.forename: Alaka
authors.initials: A
authors.lastname: Mullick
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: René
authors.initials: R
authors.lastname: Warren
authors.forename: Maria
authors.initials: M
authors.lastname: Koutroumanis
authors.forename: Claire
authors.initials: C
authors.lastname: Guilbault
authors.forename: Sophie
authors.initials: S
authors.lastname: Broussau
authors.forename: Félix
authors.initials: F
authors.lastname: Malenfant
authors.forename: Lucie
authors.initials: L
authors.lastname: Bourget
authors.forename: Linda
authors.initials: L
authors.lastname: Lamoureux
authors.forename: Rita
authors.initials: R
authors.lastname: Lo
authors.forename: Antoine W
authors.initials: AW
authors.lastname: Caron
authors.forename: Amelie
authors.initials: A
authors.lastname: Pilotte
authors.forename: Bernard
authors.initials: B
authors.lastname: Massie
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D005786:Gene Expression Regulation / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D005812:Genes, Switch / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D009154:Mutation / Q000235:genetics; D009876:Operon / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection
chemical_list: D012097:Repressor Proteins; D015534:Trans-Activators