Cloning and characterization of the gene encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase in melon (Cucumis melo L. reticulatus).
We have isolated a cDNA for Cm-HMGR, encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in melon (Cucumis melo L. reticulatus; Genbank Accession No. AB021862). Cm-HMGR encodes a polypeptide of 588 amino acids that contains two transmembrane domains and a catalytic domain. Database searches revealed that Cm-HMGR shows homology to HMG1 (63.7%) and HMG2 (70.3%) of tomato, to HMG1 (77.2%) and HMG2 (69.4%) of Arabidopsis thaliana, and to HMGR of tobacco (72.6%). Functional expression in a HMG-CoA reductase-deficient mutant yeast showed that Cm-HMGR products mediate the synthesis of mevalonate. Northern analysis revealed that the level of Cm-HMGR mRNA in the fruit increased after pollination and markedly decreased at the end of fruit enlargement. During ripening, Cm-HMGR mRNA levels increased markedly in the fruit. In parallel with mRNA expression, Cm-HMGR activity increased after pollination, whereas no Cm-HMGR activity was detectable during fruit ripening. Our results suggest that Cm-HMGR is important during early post-pollination development of the fruit in melon.
Kato-Emori
S
S
Plant Biotechnology Institute, Ibaraki Agricultural Center, Iwama, Japan.
Higashi
K
K
Hosoya
K
K
Kobayashi
T
T
Ezura
H
H
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D005638:Fruit / Q000235:genetics* / Q000502:physiology; D017343:Genes, Plant; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics* / Q000378:metabolism; D025782:Hydroxymethylglutaryl-CoA-Reductases, NADP-dependent; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D008565:Membrane Proteins; D006903:Hydroxymethylglutaryl CoA Reductases; D025782:Hydroxymethylglutaryl-CoA-Reductases, NADP-dependent