title: Regulation of transcription in mammalian cells by yeast Leu3p and externally supplied inducer.
abstract: The Leu3 protein of yeast is a dual-function regulator, stimulating transcription when the inducer alpha-isopropylmalate (alpha-IPM) is present and suppressing transcription when the inducer is absent. Here we show that Leu3p retains both its positive and negative regulatory properties when expressed in mammalian cells or when added to a mammalian nuclear extract. Alpha-IPM stimulates reporter gene expression 15-20-fold, both in vivo and in vitro. The concentration of alpha-IPM required for half-maximal stimulation in vitro is 2.5 x 10(-4) M. No yeast-specific factors other than Leu3p itself are required for up- or down-regulation. Since alpha-IPM is not metabolized in mammalian cells, the Leu3p-alpha-IPM system might be useful in gene therapy and other studies as a highly specific, externally controlled on/off switch of gene expression.
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: H
authors.initials: H
authors.lastname: Guo
authors.forename: G B
authors.initials: GB
authors.lastname: Kohlhaw
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008293:Malates / Q000494:pharmacology*; D051379:Mice; D011487:Protein Conformation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C063667:LEU3 protein, S cerevisiae; D008293:Malates; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; C005906:alpha-isopropylmalate