Cloning and expression of squalene synthase cDNA from hot pepper (Capsicum annuum L.).
We isolated and artificially expressed a cDNA clone of the Capsicum annuum squalene synthase (CASS) gene to elucidate the pattern of alternatively regulated two-branch point enzymes. The 1,674-bp CASS cDNA contained an open reading frame of 411 amino acids, yielding a predicted molecular mass of about 45 kDa. A deduced amino acid sequence comparison to other squalene syntheses showed identities with Nicotiana tabacum (91%), Nicotiana benthamiana (90%), Arabidopsis thaliana (79%), and rats (40%). The artificially expressed soluble form of the CASS enzyme was identified by the enzyme activity that converted FPP to squalene and by SDS-PAGE. A Southern blot analysis indicated that at least two copies of the squalene synthase gene exist in the hot pepper genome. In hot pepper, the regulation of the branch point enzymes, squalene synthase and sesquiterpene cyclase was investigated in the UV-challenged leaves of Capsicum annuum. The transcript level and enzyme activity of the CASS were slightly reduced by UV. However, those of the CASC were rapidly induced within 24 h and slowly decreased thereafter.
Department of Agronomy, College of Agriculture, Kyungpook National University, Daegu, Korea.
Jung-Hoon
JH
Lee
Yong-Hwi
YH
Yoon
Hak-Yoon
HY
Kim
Dong-Hyun
DH
Shin
Dal-Ung
DU
Kim
In-Jung
IJ
Lee
Kil-Ung
KU
Kim
D001483:Base Sequence; D015139:Blotting, Southern; D002212:Capsicum / Q000201:enzymology* / Q000235:genetics; D019755:Carbon-Carbon Lyases / Q000378:metabolism / Q000528:radiation effects; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014466:Ultraviolet Rays
D018076:DNA, Complementary; D013186:Farnesyl-Diphosphate Farnesyltransferase; D019755:Carbon-Carbon Lyases; C051130:trichodiene synthetase