Ecdysone during ovarian development in Locusta migratoria

Lagueux, Marie; Hirn, M.; Hoffmann, Jules A.

doi:10.1016/0022-1910(77)90116-0

Cited by 221 publications

(60 citation statements)

References 16 publications

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“…Of relevance to this is previous research in other insects, which has shown that the cells of the follicular epithelium, rather than the nurse cell complex, are involved in ecdysone biosynthesis (Lagueux et al, 1977). This has been confirmed through the expression pattern of the disembodied (dis) gene, which encodes a specific hydroxylase in the ecdysone biosynthetic pathway and is expressed in the follicular epithelium (Chávez et al, 2000).…”

Section: The Transition From Previtellogenesis To Vitellogenesismentioning

confidence: 64%

“…During the progression of vitellogenesis, ecdysteroid synthesis occurs in the cells of the follicular epithelium (Lagueux et al, 1977). However, in lepidopteran and orthopteran insects, most of the ecdysteroids produced by the follicular epithelium are inactive conjugates of ecdysone precursors and metabolites, and only very small amounts of active 20E are detected (Mizuno et al, 1981;Tawfik et al, 1999).…”

Section: Ecdysteroidogenesis and Resumption Of Meiosismentioning

confidence: 99%

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Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Swevers

2005

Comprehensive Molecular Insect Science

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Section: The Transition From Previtellogenesis To Vitellogenesismentioning

confidence: 64%

Section: Ecdysteroidogenesis and Resumption Of Meiosismentioning

confidence: 99%

Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Swevers

2005

Comprehensive Molecular Insect Science

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“…It remains to be tested whether the egg chamber fusions in ecd mosaic ovaries might result from a compromised signaling by the PFC. Follicle cells are thought to be the major site of ecdysone production in the ovary (Lagueux et al, 1977;Zhu et al, 1983). However, it is difficult to imagine that the relatively small ecd -clones could significantly reduce the ecdysone titer in the female.…”

Section: Discussionmentioning

confidence: 99%

Cell-autonomous roles of theecdysonelessgene inDrosophiladevelopment and oogenesis

et al. 2004

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Steroid signaling underlies developmental processes in animals. Mutations that impair steroidogenesis in the fruit fly Drosophila melanogasterprovide tools to dissect steroid hormone action genetically. The widely used temperature-sensitive mutation ecdysoneless1(ecd1) disrupts production of the steroid hormone ecdysone, and causes developmental and reproductive defects. These defects cannot be satisfactorily interpreted without analysis of the ecdgene. Here, we show that ecd encodes an as yet functionally undescribed protein that is conserved throughout eukaryotes. The ecd1 conditional allele contains an amino acid substitution, whereas three non-conditional larval lethal mutations result in truncated Ecd proteins. Consistent with its role in steroid synthesis, Ecd is expressed in the ecdysone-producing larval ring gland. However, development of ecd-null early larval lethal mutants cannot be advanced by Ecd expression targeted to the ring gland or by hormone feeding. Cell-autonomous ecd function, suggested by these experiments, is evidenced by the inability of ecd– clones to survive within developing imaginal discs. Ecd is also expressed in the ovary, and is required in both the follicle cells and the germline for oocyte development. These defects, induced by the loss of ecd, provide the first direct evidence for a cell-autonomous function of this evolutionarily conserved protein.

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“…It may well appear that various oxygenation steps from a sterol precursor to ecdysone in prothoracic glands are also dependent on cytochrome P-450 monooxygenases. Similarly, the synthesis of ecdysteroids in abdominal tissues [46] and adult ovaries [47,48] may also prove to be dependent on cytochrome P-450. Moreover, data of Hammock [49] on the epoxidation of methyl farnesoate by cockroach corpora allata are strongly suggestive of a cytochrome P-450 involvement in juvenile hormone synthesis.…”

Section: Discussionmentioning

confidence: 99%

Ecdysterone Biosynthesis: A Microsomal Cytochrome-P-450-Linked Ecdysone 20-Monooxygenase from Tissues of the African Migratory Locust

Durst

1978

Eur J Biochem

128

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Ecdysone 20-monooxygenase, an enzyme which convem ecdysone to ecdysterone (the major moulting hormone of insects) has been characterized in cell-free preparations of tissues from African migratory locust. The product of the reaction has been identified as ecdysterone on the basis of several microchemical derivatization and chromatographic methods.Ecdysone 20-monooxygenase activity is located primarily in the microsomal fraction which also carries NADPH cytochrome c reductase and cytochrome P-450, as shown by sucrose density gradient centrifugation.Optimal conditions for the ecdysone 20-monooxygenase assay have been determined. The enzyme has a K,,, for ecdysone of 2.7 x lo-' M and is competitively inhibited by ecdysterone Ecdysone 20-monooxygenase is a typical cytochrome P-450 linked monooxygenase : the reaction requires O2 and is inhibited by CO, an effect partially reversed by white light. The enzyme is effectively inhibited by several specific monooxygenase inhibitors and by sulfhydryl reagents, but not by cyanide ions. Ecdysone elicits a type I difference spectrum when added to oxidized microsomes.NADPH acts as preferential electron donor. The transfer of reducing equivalents proceeds through NADPH cytochrome c (P-450) reductase : ecdysone 20-monooxygenase is inhibited by cytochrome c. Both NADPH cytochrome c reductase and' ecdysone 20-monooxygenase are inhibited by NADP' and show a similar K, for NADRH.The Malpighian tubules have the highest specific activity of ecdysone 20-monooxygenase, while fat body contain most of the cytochrome P-450 and NADPH cytochrome c reductase.( K~ = 7.5 x 10-7 M).Recent studies have established the role of the prothoracic glands in the secretion of ecdysone during larval development of insects [1,2]. This steroid is however not the major moulting hormone of insect larvae. Indeed, ecdysone serves in peripheral tissues as a precursor to ecdysterone (20-hydroxyecdysone) [3] which is also biologically more potent than ecdysone in vitro in several tests of moulting hormone activity [4].Enzymes. Ecdysone 20-monooxygenase, or ecdysone, reduced flavoprotein : oxygen oxidoreductase (20-hydroxylating) (EC 1.14.14.-); NADPH-cytochrome c (P-450) reductase (EC 1.6.2.4).Trivial Names. Ecdysone, 2fi,3fl,14~~,22R,25-pentahydroxy-5p-cholest-7-en-6-one; ecdysterone or 20-hydroxy-ecdysone, 2P,3/j14a,20R,22R,25-hexahydroxy-S~-cholest-7-en-6-one. (The use of 'a-ecdysone' for ecdysone and '8-ecdysone' for ecdysterone is an abuse and should be avoided.)While it appears that the secretion of ecdysone by the prothoracic glands and the inactivation of ecdysteroids vary during larval development [5,6], it has also become clear that the relative amounts of ecdysone and ecdysterone (and other ecdysteroids?) are fluctuating [7,8]. The enzyme responsible for the conversion of ecdysone to ecdysterone, ecdysone 20-monooxygenase, thus plays a central role in the delicate hormonal balance which controls the moulting process. It was felt that a precise characterization of this enzyme was a prerequisite to studies...

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Ecdysone during ovarian development in Locusta migratoria

Cited by 221 publications

References 16 publications

Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Cell-autonomous roles of theecdysonelessgene inDrosophiladevelopment and oogenesis

Ecdysterone Biosynthesis: A Microsomal Cytochrome-P-450-Linked Ecdysone 20-Monooxygenase from Tissues of the African Migratory Locust

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