Immunological analysis of developmental changes in ecdysone 20-mono-oxygenase expression in the cotton leafworm, Spodoptera littoralis.
The developmental changes in ecdysone 20-mono-oxygenase during the sixth larval instar of the cotton leafworm, Spodoptera littoralis, were investigated. The specific activity of mitochondrial ecdysone 20-mono-oxygenase in the fat-body exhibited a distinct peak at 72 h, at which time the larvae stop feeding. Immunoblot analyses, using antibodies raised against components of vertebrate mitochondrial steroidogenic enzyme systems [anti-(cytochrome P-450scc), anti-(cytochrome P-450(11) beta), anti-adrenodoxin and anti-(adrenodoxin reductase) antibodies], revealed the presence of specific immunoreactive polypeptides in fat-body mitochondrial extracts. In addition, these antibodies effectively inhibited fat-body mitochondrial ecdysone 20-mono-oxygenase activity. This suggests that the S. littoralis steroid-hydroxylating system(s) may contain polypeptide components analogous to those present in vertebrates. A close correlation between developmental changes in mitochondrial ecdysone 20-mono-oxygenase activity and the abundance of polypeptides (approx. 66 kDa and 50 kDa) recognized by the anti-(cytochrome P-450(11) beta) antibody and a polypeptide (approx. 52 kDa) recognized by the anti-(adrenodoxin reductase) antibody were observed in both fat-body and midgut. These results suggest that developmental changes in the abundance of components of the ecdysone 20-mono-oxygenase system may play an important role in the developmental regulation of the enzyme expression and, hence, of 20-hydroxyecdysone titre.
Chen
J H
JH
Department of Biochemistry, University of Liverpool, U.K.
Hara
T
T
Fisher
M J
MJ
Rees
H H
HH
D000325:Adrenodoxin / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001189:Aryl Hydrocarbon Hydroxylases; D015153:Blotting, Western; D002417:Cattle; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000276:immunology / Q000378:metabolism; D019405:Cytochrome P-450 CYP11B2; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism; D005216:Fat Body / Q000201:enzymology; D005287:Ferredoxin-NADP Reductase / Q000276:immunology / Q000378:metabolism; D007814:Larva / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D009036:Moths / Q000196:embryology / Q000201:enzymology*; D013252:Steroid 11-beta-Hydroxylase / Q000276:immunology / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000096:biosynthesis* / Q000187:drug effects / Q000276:immunology
D000906:Antibodies; D000325:Adrenodoxin; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; D019405:Cytochrome P-450 CYP11B2; D013252:Steroid 11-beta-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme; C020095:ecdysone 20-hydroxylase; D005287:Ferredoxin-NADP Reductase