title: Molecular and functional characterization of a cDNA encoding 4-hydroxy-3-methylbut-2-enyl diphosphate reductase from Dunaliella salina.
abstract: In green algae, the final step of the plastidial methylerythritol phosphate (MEP) pathway is catalyzed by 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR; EC: 1.17.1.2), an enzyme proposed to play a key role in the regulation of isoprenoid biosynthesis. Here we report the isolation and functional characterization of a 1959-bp Dunaliella salina HDR (DsHDR) cDNA encoding a deduced polypeptide of 474 amino acid residues. Phylogenetic analysis implied a cyanobacterial origin for plant and algal HDR genes. Steady-state DsHDR transcript levels were higher in D. salina cells submitted to nutritional depletion, high salt and/or high light, suggesting that DsHDR may respond to the same environmental cues as genes involved in carotenoid biosynthesis.
authors.affiliation: Centre of Marine Sciences, University of Algarve, Campus de Gambelas, Faro 8005-139, Portugal.
authors.forename: Ana A
authors.initials: AA
authors.lastname: Ramos
authors.forename: Ana R
authors.initials: AR
authors.lastname: Marques
authors.forename: Marta
authors.initials: M
authors.lastname: Rodrigues
authors.forename: Nuno
authors.initials: N
authors.lastname: Henriques
authors.forename: Alexandra
authors.initials: A
authors.lastname: Baumgartner
authors.forename: Rita
authors.initials: R
authors.lastname: Castilho
authors.forename: Bertram
authors.initials: B
authors.lastname: Brenig
authors.forename: João C
authors.initials: JC
authors.lastname: Varela
mesh_terms: D020418:Algal Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D015152:Blotting, Northern; D000460:Chlorophyta / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
chemical_list: D020418:Algal Proteins; D018076:DNA, Complementary; D010088:Oxidoreductases