Cloning and functional characterization of two cDNAs encoding NADPH-dependent 3-ketoacyl-CoA reductased from developing cotton fibers  

作　　者：YongMeiQIN FrancoisMAPUJOL YongHuiSHI JianXunFENG YiMingLIU AlexanderJKASTANIOTIS JKalervoHILTUNEN YuXianZHU 

机构地区：[1]NationalLaboratoryofProteinEngineeringandPlantGeneticEngineering,CollegeofLifeSciences,PekingUniversity,Beijing,100871,China [2]BiocenterOuluandDepartmentofBiochemistry,UniversityofOulu,P.O.Box3000,FIN-90014UniversityofOulu,Finland

出　　处：《Cell Research》2005年第6期465-473,共9页细胞研究（英文版）

基　　金：supported by grants from China Na-tional Basic Research Program (NO. 2004CB117302);National Natural Science Foundation of China (No.30470171);the Sigrid Jusélius Foundation Finland and the Academy of Finland

摘　　要：Genes encoding enzymes involved in biosynthesis of very long chain fatty acids were significantly up-regulatedduring early cotton fiber development. Two cDNAs, GhKCR1 and GhKCR2 encoding putative cotton 3-ketoacyl-CoAreductases that catalyze the second step in fatty acid elongation, were isolated from developing cotton fibers. GhKCR1and 2 contain open reading frames of 963 bp and 924 bp encoding proteins of 320 and 307 amino acid residues,respectively. Quantatitive RT-PCR analysis showed that both these genes were highly preferentially expressed duringthe cotton fiber elongation period with much lower levels recovered from roots, stems and leaves. GhKCR1 and 2showed 30%-32% identity to Saccharomyces cerevisiae Ybr159p at the deduced amino acid level. These cotton cDNAswere cloned and expressed in yeast haploid ybr159w? mutant that was deficient in 3-ketoacyl-CoA reductase activity.Wild-type growth rate was restored in ybr159w? cells that expressed either GhKCR1 or 2. Further analysis showed thatGhKCR1 and 2 were co-sedimented within the membranous pellet fraction after high-speed centrifugation, similar to theyeast endoplasmic reticulum marker ScKar2p. Both GhKCR(s) showed NADPH-dependent 3-ketoacyl-CoA reductaseactivity in an in vitro assay system using palmitoyl-CoA and malonyl-CoA as substrates. Our results suggest thatGhKCR1 and 2 are functional orthologues of ScYbr159p.

关 键 词：very-long-chain fatty acids endoplasmic reticulum fatty acid elongation system 3-ketoacyl-CoA reductase Gossypium hirsutum short-chain alcohol dehydrogenase/reductase protein family. 

分 类 号：S562[农业科学—作物学]