Patent ID: 8653046

Claim:
An in vitro method for controlling transgene expression, the method comprising: (i) transfecting isolated mammalian cells with a first vector comprising a polynucleotide sequence operably linked to a constitutively active promoter sequence, wherein said polynucleotide sequence encoding a fusion protein consisting of a Pseudomonas putida DOT-T1E-derived bacterial repressor protein TtgR and a transactivation domain, or a fusion protein consisting of TtgR and a transrepressor domain; and transfecting said isolated mammalian cells with a second vector comprising a TtgR-specific operator (O TtgR ) sequence operably linked to a promoter sequence, wherein said promoter sequence is operably linked to a polynucleotide sequence encoding an endogenous or exogenous protein; wherein expression of TtgR-transactivation domain fusion protein in said cells induces expression of said endogenous or exogenous protein; or wherein expression of TtgR-transrepressor domain fusion protein in said cells inhibits expression of said endogenous or exogenous protein; or transfecting isolated mammalian cells with a single vector comprising a first polynucleotide sequence operably linked to a constitutively active promoter sequence, wherein said polynucleotide sequence encoding a fusion protein consisting of a TtgR and a transactivation domain, or a fusion protein consisting of a TtgR and a transrepressor domain; and a second polynucleotide sequence comprising an O TtgR sequence operably linked to a promoter sequence, wherein said promoter sequence is operably linked to a polynucleotide sequence encoding an endogenous or exogenous protein; wherein expression of TtgR-transactivation domain fusion protein in said cells induces expression of said endogenous or exogenous protein; or wherein expression of TtgR-transrepressor domain fusion protein in said cells inhibits expression of said endogenous or exogenous protein; and (ii) contacting said cells with a non-toxic micromolar concentration range of a skin permeating compound selected from phloretin and butylparaben, wherein said skin permeating compound dissociates TtgR-transactivation domain fusion protein from O TtgR and results in repression of said protein expression; or wherein said skin permeating compound dissociates TtgR-transrepressor domain fusion protein from O TtgR and results in enhancement of said protein expression.