Identification of a sterol Delta7 reductase gene involved in desmosterol biosynthesis in Mortierella alpina 1S-4.
Molecular cloning of the gene encoding sterol Delta7 reductase from the filamentous fungus Mortierella alpina 1S-4, which accumulates cholesta-5,24-dienol (desmosterol) as the main sterol, revealed that the open reading frame of this gene, designated MoDelta7SR, consists of 1,404 bp and codes for 468 amino acids with a molecular weight of 53,965. The predicted amino acid sequence of MoDelta7SR showed highest homology of 51% with that of sterol Delta7 reductase (EC 1.3.1.21) from Xenopus laevis (African clawed frog). Heterologous expression of the MoDelta7SR gene in yeast Saccharomyces cerevisiae revealed that MoDelta7SR converts ergosta-5,7-dienol to ergosta-5-enol (campesterol) by the activity of Delta7 reductase. In addition, with gene silencing of MoDelta7SR gene by RNA interference, the transformant accumulated cholesta-5,7,24-trienol up to 10% of the total sterols with a decrease in desmosterol. Cholesta-5,7,24-trienol is not detected in the control strain. This indicates that MoDelta7SR is involved in desmosterol biosynthesis in M. alpina 1S-4. This study is the first report on characterization of sterol Delta7 reductase from a microorganism.
Zhang
Shuo
S
Division of Applied Life of Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan. sim@kais.kyoto-u.ac.jp
Sakuradani
Eiji
E
Shimizu
Sakayu
S
D000818:Animals; D001483:Base Sequence; D002762:Cholecalciferol / Q000031:analogs & derivatives / Q000378:metabolism; D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D003897:Desmosterol / Q000378:metabolism*; D004875:Ergosterol / Q000031:analogs & derivatives / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D015870:Gene Expression; D020868:Gene Silencing; D008969:Molecular Sequence Data; D015394:Molecular Structure; D008970:Molecular Weight; D020094:Mortierella / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D010840:Phytosterols / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013261:Sterols / Q000032:analysis / Q000302:isolation & purification; D014982:Xenopus laevis / Q000235:genetics
D004271:DNA, Fungal; D010840:Phytosterols; D013261:Sterols; C007041:cholesta-5,7,24-trien-3 beta-ol; D002762:Cholecalciferol; D003897:Desmosterol; C012287:22,23-dihydroergosterol; C021273:campesterol; D002784:Cholesterol; D044925:Oxidoreductases Acting on CH-CH Group Donors; C019995:7-dehydrocholesterol reductase; D004875:Ergosterol