title: Molecular cloning and characterization of gene coding for γ-tocopherol methyltransferase from lettuce (Lactuca sativa).
abstract: γ-tocopherol methyltransferase is an important  rate-limiting enzyme involved in tocopherol biosynthesis. The full-length cDNA  encoding γ-tocopherol methyltransferase (designated  as LsTMT) was cloned from Lactuca sativa for the first time by  rapid amplification of cDNA ends and characterized by means of quantitative  RT-PCR. The full-length cDNA of LsTMT was 1131 bp, with an open reading  frame of 897 bp encoding a γ-tocopherol methyltransferase protein of 298 amino  acids, with a calculated molecular mass of 33.06 kDa and an isoelectric point  of 5.86. Comparative analysis revealed that LsTMT has a close similarity  with γ-TMTs from other plant species. Bioinformatic  analysis indicated that LsTMT shares a common evolutionary origin based  on sequence similarity and has the closest relationship to γ-TMT from the sunflower, Helianthus  annuus. Based on quantitative RT-PCR analysis, we found that expression of LsTMT is induced and strengthened by oxidative stresses such as strong light and  drought. The cloning and characterization of LsTMT will be helpful to  further understanding its role in the tocopherol biosynthesis pathway. We  consider it to be a candidate gene for metabolic engineering of vitamin E in  vegetable crops.
authors.affiliation: School of Agriculture and Biology, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: Tang
authors.forename: W W
authors.initials: WW
authors.lastname: Ren
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: K X
authors.initials: KX
authors.lastname: Tang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D019295:Computational Biology; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D006368:Helianthus / Q000235:genetics; D018545:Lactuca / Q000201:enzymology / Q000235:genetics*; D008027:Light; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D016366:Open Reading Frames; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D024504:gamma-Tocopherol / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D024504:gamma-Tocopherol; D008780:Methyltransferases; C047259:gamma-tocopherol methyltransferase