title: Protein-DNA interactions in the promoter region of the Phycomyces carB and carRA genes correlate with the kinetics of their mRNA accumulation in response to light.
abstract: Carotene biosynthesis in Phycomyces is photoinducible and carried out by phytoene dehydrogenase (encoded by carB) and a bifunctional enzyme possessing lycopene cyclase and phytoene synthase activities (carRA). A light pulse followed by periods of darkness produced similar biphasic responses in the expression of the carB and carRA genes, indicating their coordinated regulation. Specific binding complexes were formed between the carB-carRA intergenic region and protein extracts from wild type mycelia grown in the dark or 8min after irradiation. These two conditions correspond to the points at which the expression of both genes is minimal, suggesting that these binding complexes are involved in the down-regulation of photocarotenogenesis in Phycomyces. Protein extracts from carotene mutants failed to form the dark retardation complex, suggesting a role of these genes in the regulation of photocarotenogenesis. In contrast, protein extracts from phototropic mutants formed dark retardation complexes identical to that of the wild type.
authors.affiliation: Departamento de Microbiología y Genética, Universidad de Salamanca, Spain.
authors.forename: Catalina
authors.initials: C
authors.lastname: Sanz
authors.forename: Ernesto P
authors.initials: EP
authors.lastname: Benito
authors.forename: Margarita
authors.initials: M
authors.lastname: Orejas
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Alvarez
authors.forename: Arturo P
authors.initials: AP
authors.lastname: Eslava
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015536:Down-Regulation / Q000528:radiation effects; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects*; D015966:Gene Expression Regulation, Fungal / Q000528:radiation effects; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D019753:Intramolecular Lyases / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008027:Light; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010800:Phycomyces / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D011401:Promoter Regions, Genetic / Q000528:radiation effects*; D011485:Protein Binding / Q000528:radiation effects; D020871:RNA Stability / Q000528:radiation effects; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D010088:Oxidoreductases; C022398:phytoene dehydrogenase; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase