Functional analysis of the regulatory region adjacent to the cargB gene of Saccharomyces cerevisiae. Nucleotide sequence, gene fusion experiments and cis-dominant regulatory mutation analysis.
In Saccharomyces cerevisiae the expression of the cargB gene (coding for ornithine aminotransferase) is submitted to dual regulation: an induction by allophanate and a specific induction process by arginine. We have determined the nucleotide sequence of the cargB gene along with its 5' region. The coding portion of the gene encodes a protein of 423 amino acid residues with a calculated Mr value of 46049. To characterize further the regulatory mechanisms modulating the expression of the gene we have analyzed fusions of several fragments of the 5' non-coding region to lacZ, compared the 5' sequences of the cargA (coding for arginase) and cargB coregulated genes and determined the nature of two constitutive cis-dominant mutations affecting the arginine control. These approaches allowed us to define three domains in the 5' non-coding region. The upstream one is implicated in the induction by allophanate. The two other domains are involved in the specific control by arginine; the target of the ARGR gene products, that mediate a positive regulation by arginine, lies upstream of another site where a repression by the CARGRI molecule occurs. The constitutive cargB+O- mutations are located in this repressor domain. The 5' non-coding region of cargA presents the same two-domain organization. These two domains contain three sequences homologous to the cargA and cargB 5' regions.
Degols
G
G
Laboratoire de Microbiologie, Faculté des Sciences, Université Libre de Bruxelles, Belgium.
D000595:Amino Acid Sequence; D001120:Arginine / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D005786:Gene Expression Regulation / Q000187:drug effects; D005800:Genes, Fungal; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009154:Mutation; D009953:Ornithine-Oxo-Acid Transaminase / Q000235:genetics*; D010957:Plasmids; D012045:Regulatory Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D000637:Transaminases / Q000235:genetics*; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology; D001616:beta-Galactosidase / Q000235:genetics
C054306:allophanic acid; D014508:Urea; D001120:Arginine; D000637:Transaminases; D009953:Ornithine-Oxo-Acid Transaminase; D004262:DNA Restriction Enzymes; D001616:beta-Galactosidase