title: Role of an upstream regulatory element in leucine repression of the Saccharomyces cerevisiae leu2 gene.
abstract: The expression of a number of eukaryotic genes has been shown to involve at least two sequences located upstream of the actual transcription unit: one of these sequences, centred on a widely conserved TATAAT sequence, is thought to be involved in determining the precise site of initiation of transcription; the other has a gene-specific sequence, can function at a variable distance upstream of the initiation site, and is involved in the regulation of transcription. By constructing beta-galactosidase gene fusions, to facilitate measuring gene expression in vivo, we have now defined a cis-acting regulatory element of the Saccharomyces cerevisiae leu2 gene. This element is located within a 280 base pair (bp) fragment which occurs 125 bp upstream of the leu2 translation initiation codon and which contains a short G + C-rich palindromic sequence. A fragment of the Escherichia coli transposable element Tn9 which contains a similar palindromic sequence can functionally replace the natural leu2 regulatory element. Our results are contrary to previous speculations that the leu2 gene is regulated by an attenuation mechanism.
mesh_terms: D050539:3-Isopropylmalate Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000235:genetics*; D001483:Base Sequence; D004251:DNA Transposable Elements; D004271:DNA, Fungal / Q000235:genetics; D004794:Enzyme Repression; D005786:Gene Expression Regulation; D005809:Genes, Regulator; D007930:Leucine / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D004271:DNA, Fungal; D000429:Alcohol Oxidoreductases; D050539:3-Isopropylmalate Dehydrogenase; D007930:Leucine