title: Cloning of a cDNA encoding a novel cytochrome P450 from the insect Locusta migratoria: CYP6H1, a putative ecdysone 20-hydroxylase.
abstract: The biosynthesis of the steroidal molting hormone, 20-hydroxyecdysone, of arthropods involves a series of cytochrome P450-catalyzed hydroxylations. None of the many sequences of insect cytochromes P450, known to date, is related to ecdysteroid pathways. Here, we report the cloning and sequencing of a full-length cDNA of a new cytochrome P450, classified as CYP6H1, from malpighian tubules of the locust, Locusta migratoria. The 1854 bp DNA contained an open reading frame coding for a protein of 542 amino acids, a 5'-leader sequence and a 3'-untranslated region containing a polyadenylation signal and a poly(A) tail. The encoded protein had been isolated as an ecdysone-binding cytochrome P450 from microsomes of the same tissue in previous work. The closest homolog of CYP6H1 was CYP6A2 from Drosophila with 42.1% identity. According to Northern analysis, CYP6H1 is predominantly expressed at larval instars and in malpighian tubules. Evidence is presented for a functional assignment of CYP6H1 to microsomal ecdysone 20-hydroxylase of the locust.
authors.affiliation: Research Biochemistry, Novartis Crop Protection AG, Basel, CH-4002, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Winter
authors.forename: G
authors.initials: G
authors.lastname: Bilbe
authors.forename: H
authors.initials: H
authors.lastname: Richener
authors.forename: B
authors.initials: B
authors.lastname: Sehringer
authors.forename: H
authors.initials: H
authors.lastname: Kayser
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry / Q000378:metabolism; D004440:Ecdysone / Q000096:biosynthesis; D018507:Gene Expression Regulation, Developmental; D006110:Grasshoppers / Q000201:enzymology / Q000235:genetics*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics; D008317:Malpighian Tubules / Q000201:enzymology; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D017385:Sequence Homology; D013250:Steroid Hydroxylases / Q000737:chemistry / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D012333:RNA, Messenger; D004440:Ecdysone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C020095:ecdysone 20-hydroxylase