[Isolation and characterization of a 2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase gene from Taxus media].

2C-methyl-D-erythritol 2,4-cyclodiphosphate (MEC) synthase (MECS, EC: 4.6.1.12) is the fifth enzyme of the nonmevalonate terpenoid pathway for isopentenyl diphosphate biosynthesis and further Taxol biosynthesis. The full-length MECS cDNA sequence (GenBank accession number DQ286391) was cloned and characterized for the first time from Taxus media, using Rapid Amplification of cDNA Ends (RACE) technique. The full-length cDNA of Tmmecs was 1081 bp containing a 741 bp open reading frame (ORF) encoding a peptide of 247 amino acids with a calculated molecular mass of 26.1 kDa and an isoelectric point of 8.97. Comparative and bioinformatic analyses revealed that TmMECS had extensive homology with MECSs from other plant species. Phylogenetic analysis indicated that TmMECS was more ancient than other plant MECSs. Southern blot analysis revealed that Tmmecs belonged to a small gene family. Tissue expression pattern analysis indicated that Tmmecs expressed constitutively in all tissues including roots, stems and leaves. The cloning and characterization of Tmmecs will be helpful to understand more about the role of MECS involved in the Taxol biosynthesis at the molecular level.