Lanosterol synthase in dicotyledonous plants.
Sterols are important as structural components of plasma membranes and precursors of steroidal hormones in both animals and plants. Plant sterols show a wide structural variety and significant structural differences from those of animals. To elucidate the origin of structural diversity in plant sterols, their biosynthesis has been extensively studied [Benveniste (2004) Annu. Rev. Plant. Biol. 55: 429, Schaller (2004) Plant Physiol. Biochem. 42: 465]. The differences in the biosynthesis of sterols between plants and animals begin at the step of cyclization of 2,3-oxidosqualene, which is cyclized to lanosterol in animals and to cycloartenol in plants. However, here we show that plants also have the ability to synthesize lanosterol directly from 2,3-oxidosqualene, which may lead to a new pathway to plant sterols. The Arabidopsis gene At3g45130, designated LAS1, encodes a functional lanosterol synthase in plants. A phylogenetic tree showed that LAS1 belongs to the previously uncharacterized branch of oxidosqualene cyclases, which differs from the cycloartenol synthase branch. Panax PNZ on the same branch was also shown to be a lanosterol synthase in a yeast heterologous expression system. The higher diversity of plant sterols may require two biosynthetic routes in steroidal backbone formation.
RIKEN Plant Science Center, 1-7-22 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan.
Masashi
M
Suzuki
Ting
T
Xiang
Kiyoshi
K
Ohyama
Hikaru
H
Seki
Kazuki
K
Saito
Toshiya
T
Muranaka
Hiroaki
H
Hayashi
Yuji
Y
Katsube
Tetsuo
T
Kushiro
Masaaki
M
Shibuya
Yutaka
Y
Ebizuka
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology; D018744:DNA, Plant / Q000032:analysis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D017343:Genes, Plant / Q000235:genetics; D019751:Intramolecular Transferases / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D007810:Lanosterol / Q000096:biosynthesis*; D019684:Magnoliopsida / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology; D005894:Panax / Q000235:genetics / Q000502:physiology; D010802:Phylogeny; D010840:Phytosterols / Q000032:analysis / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology; D013185:Squalene / Q000031:analogs & derivatives / Q000378:metabolism
C002821:2,3-oxidosqualene; D029681:Arabidopsis Proteins; D018744:DNA, Plant; C098171:LAS1 protein, S cerevisiae; D009687:Nuclear Proteins; D010840:Phytosterols; D029701:Saccharomyces cerevisiae Proteins; D007810:Lanosterol; D013185:Squalene; D019751:Intramolecular Transferases; C513124:LAS1 protein, Arabidopsis; C021924:lanosterol synthase; C021923:cycloartenol synthase