Host cells and methods using a repressor polypeptide and an inducible promoter for gene expression

摘要

The present invention provides for a system comprising (a) a first nucleic acid comprising a nucleotide sequence encoding a nucleotide sequence of interest operatively linked to a promoter comprising a repressor polypeptide binding site, and (b) a second nucleic acid comprising a nucleotide sequence encoding a repressor polypeptide having at least 70% amino acid identity with EilR, SmvR, KmrR, RcdA, or QacR; wherein expression of the nucleotide sequence of interest from the promoter is induced by the presence of a hydrophobic inducer, such as a hydrophobic cation inducer, such as a triarylmethane, acridine, phenazine, phenothiazine, or xanthene.

主权项

1. A system comprising (a) a first nucleic acid comprising a nucleotide sequence encoding a nucleotide sequence of interest operatively linked to a promoter comprising an EilR binding site or a QacR binding site, and (b) a second nucleic acid comprising a nucleotide sequence encoding a repressor polypeptide; with the proviso that (i) when the promoter comprises an EilR binding site, the repressor polypeptide comprises an amino acid sequence comprising a biologically active fragment having at least 70% amino acid identity with one of SEQ ID NO:1-3 and 15, and (ii) when the promoter comprises a QacR binding site, the repressor polypeptide comprises an amino acid sequence comprising a biologically active fragment having at least 70% amino acid identity with SEQ ID NO:4; and (i) when the repressor polypeptide has an amino acid sequence consisting of SEQ ID NO:1, the first and second nucleic acids are not the same nucleic acid and/or the nucleotide sequence of interest does not encode green fluorescence protein (GFP), and (ii) when the repressor polypeptide has an amino acid sequence consisting of SEQ ID NO:4, the first and second nucleic acids are not the same nucleic acid and/or the nucleotide sequence of interest does not encode chloramphenicol acetyltransferase (CAT); wherein expression of the nucleotide sequence of interest from the promoter is induced by the presence of a hydrophobic inducer.