title: Positive and negative transcriptional control by heme of genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase in Saccharomyces cerevisiae.
abstract: Responses of the yeast genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase, HMG1 and HMG2, to in vivo changes in heme concentrations were investigated. Expression of the genes was determined by direct measurement of the mRNA transcribed from each gene, by direct assay of the enzyme activity encoded by each gene, and by measurement of the expression of lacZ fusions to the control regions of each gene. These studies indicated that expression of HMG1 was stimulated by heme, whereas expression of HMG2 was repressed by heme. The effect of heme on HMG1 expression was mediated by the HAP1 transcriptional regulator and was independent of HAP2. Thus, the genes encoding the 3-hydroxy-3-methylglutaryl coenzyme A reductase isozymes join a growing list of gene pairs that are regulated by heme in opposite ways.
authors.affiliation: Department of Biochemistry, University of California, Berkeley 94720.
authors.forename: M
authors.initials: M
authors.lastname: Thorsness
authors.forename: W
authors.initials: W
authors.lastname: Schafer
authors.forename: L
authors.initials: L
authors.lastname: D'Ari
authors.forename: J
authors.initials: J
authors.lastname: Rine
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005838:Genotype; D006418:Heme / Q000378:metabolism*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D006418:Heme; D006903:Hydroxymethylglutaryl CoA Reductases