A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis.
A cDNA encoding a cytochrome P450 enzyme was isolated from a cDNA library of the corpora allata (CA) from reproductively active Diploptera punctata cockroaches. This P450 from the endocrine glands that produce the insect juvenile hormone (JH) is most closely related to P450 proteins of family 4 and was named CYP4C7. The CYP4C7 gene is expressed selectively in the CA; its message could not be detected in the fat body, corpora cardiaca, or brain, but trace levels of expression were found in the midgut and caeca. The levels of CYP4C7 mRNA in the CA, measured by ribonuclease protection assays, were linked to the activity cycle of the glands. In adult females, CYP4C7 expression increased immediately after the peak of JH synthesis, reaching a maximum on day 7, just before oviposition. mRNA levels then declined after oviposition and during pregnancy. The CYP4C7 protein was produced in Escherichia coli as a C-terminal His-tagged recombinant protein. In a reconstituted system with insect NADPH cytochrome P450 reductase, cytochrome b5, and NADPH, the purified CYP4C7 metabolized (2E,6E)-farnesol to a more polar product that was identified by GC-MS and by NMR as (10E)-12-hydroxyfarnesol. CYP4C7 converted JH III to 12-trans-hydroxy JH III and metabolized other JH-like sesquiterpenoids as well. This omega-hydroxylation of sesquiterpenoids appears to be a metabolic pathway in the corpora allata that may play a role in the suppression of JH biosynthesis at the end of the gonotrophic cycle.
Sutherland
T D
TD
Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
Unnithan
G C
GC
Andersen
J F
JF
Evans
P H
PH
Murataliev
M B
MB
Szabo
L Z
LZ
Mash
E A
EA
Bowers
W S
WS
Feyereisen
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003058:Cockroaches / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000072470:Cytochrome P450 Family 4; D017931:DNA Primers; D004926:Escherichia coli; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D019476:Insect Proteins; D007605:Juvenile Hormones / Q000096:biosynthesis*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010058:Oviposition; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D017931:DNA Primers; D019476:Insect Proteins; D007605:Juvenile Hormones; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C115458:CYP4C7 protein, Diploptera punctata; D000072470:Cytochrome P450 Family 4