title: Characterization and expression of two cDNA encoding 3-Hydroxy-3-methylglutaryl coenzyme A reductase isoforms in coffee (Coffea arabica L.).
abstract: In higher plants there are two independent pathways for isoprenoid biosynthesis, located in the cytosol (mevalonic acid or MVA pathway) or in the plastids [methylerythritol phosphate (MEP) pathway]. The 3-hydroxy-3-methyglutaryl-CoA reductase (HMGR) is the first committed step in the MVA pathway. Using the information available from the Brazilian Coffee Genome Project, we found 13 ESTs that originated two isoforms, CaHMGR1 and CaHMGR2, for the enzyme HMGR of Coffea arabica. A complementary DNA encoding the isoform CaHMGR1 was cloned, and its complete nucleotide sequence determined. The full-length cDNA of CaHMGR1 was 2,242 bp containing a 1,812-bp ORF encoding 604 amino acids. Bioinformatic analyses revealed that the deduced CaHMGR1 had extensive homology with other plant HMGRs and contained two transmembrane domains and two putative HMGR binding sites and two NADP(H)-binding sites. Under normal growth conditions, transcripts of isoform CaHMRG1 were detected in fruit tissues (pulp, perisperm, and endosperm) only at the initial stages of development, flower buds and leaves. CaHMRG2 was expressed in all tissues and during all fruit development stages examined. These results suggest a constitutive expression of isoform CaHMGR2, while the isoform CaHMGR1 shows temporal and tissue-specific transcriptional activation.
authors.affiliation: Biotechnology Graduation Program-UEL, Londrina, PR, Brazil.
authors.forename: Iris
authors.initials: I
authors.lastname: Tiski
authors.forename: Pierre
authors.initials: P
authors.lastname: Marraccini
authors.forename: David
authors.initials: D
authors.lastname: Pot
authors.forename: Luiz Gonzaga Esteves
authors.initials: LG
authors.lastname: Vieira
authors.forename: Luiz Filipe Protasio
authors.initials: LF
authors.lastname: Pereira
mesh_terms: D000595:Amino Acid Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D040503:Coffea / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics*; D015870:Gene Expression; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics* / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D035261:Plant Components, Aerial / Q000201:enzymology / Q000235:genetics; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013729:Terpenes / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D013729:Terpenes; D006903:Hydroxymethylglutaryl CoA Reductases