Terpenoid omega-hydroxylase (CYP4C7) messenger RNA levels in the corpora allata: a marker for ovarian control of juvenile hormone synthesis in Diploptera punctata

Citation
Td. Sutherland et al., Terpenoid omega-hydroxylase (CYP4C7) messenger RNA levels in the corpora allata: a marker for ovarian control of juvenile hormone synthesis in Diploptera punctata, J INSECT PH, 46(8), 2000, pp. 1219-1227
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Entomology/Pest Control",Physiology
Journal title
JOURNAL OF INSECT PHYSIOLOGY
ISSN journal
0022-1910 → ACNP
Volume
46
Issue
8
Year of publication
2000
Pages
1219 - 1227
Database
ISI
SICI code
0022-1910(200008)46:8<1219:TO(MRL>2.0.ZU;2-Q
Abstract
Ribonuclease protection assays were used to measure changes in allatal tran script levels of the CYP4C7 gene which encodes a cytochrome P450 terpenoid omega-hydroxylase thought to play a role in the metabolism of JH and its pr ecursors. Denervation of the corpora allata does not affect the pattern of expression of the CYP4C7 gene. Transplantation experiments show that CYP4C7 mRNA levels are dependent on a humoral factor characteristic of the reprod uctive state of the insect. Messenger RNA levels rise substantially in mate d or denervated females, or in mated or virgin females treated with hydropr ene, when the follicle length is over 1.5 mm. Vitellogenic ovaries however exert a negative influence on CYP4C7 expression, as ovariectomy in mated fe males causes a premature rise in CYP4C7 mRNA levels. The half-life of the C YP4C7 transcript is approx. 2 h when the corpora allata are incubated in vi tro. Under these conditions, coincubation with a post-vitellogenic ovary ma intains high CYP4C7 transcript levels in the glands. Excess juvenile hormon e or analog applied at the end of vitellogenesis blocks ovulation or causes abortion of embryos deposited in the brood sac. We conclude that expressio n of the CYP4C7 gene is tightly controlled by the ovary, and it coincides w ith the ovarian signal to rum off juvenile hormone synthesis. The role of t he CYP4C7 enzyme may be to ensure the clearance of allatal juvenile hormone and its precursors at the end of the gonotrophic cycle. (C) 2000 Elsevier Science Ltd. All rights reserved.