Regulation of JH titers: The relevance of degradative enzymes and binding proteins

Kort, C.A.D. de; Granger, Noelle A.

doi:10.1002/(sici)1520-6327(1996)33:1<1::aid-arch1>3.0.co;2-2

Cited by 112 publications

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“…37) So far, two definitive pathways have been described for the metabolic degradation of JH: hydration of the epoxide moiety by epoxide hydrolases and hydrolysis of the methyl ester moiety by soluble esterases. 35,[38][39][40] JH epoxide hydrolase (JHEH) was purified and characterized from the eggs of M. sexta, 41) and the cDNA has been cloned from lepidopteran species [42][43][44] and the cat flea Ctenocephalides felis. 45) Most of the research on JH metabolism has focused on JH esterases (JHE).…”

Section: Biosynthesis Transport and Metabolism Of Juvenile Hormonementioning

confidence: 99%

Insect juvenile hormone action as a potential target of pest management

Minakuchi

Riddiford

2006

J. Pestic. Sci.

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Juvenile hormone (JH) is a sesquiterpenoid hormone that regulates growth and development in insects. Since JH is a hormone specific to insects and other arthropods, compounds disrupting JH action in insects are expected to be ideal insecticides with low toxicity to non-target organisms. Many natural or synthetic analogs with JH-like or anti-JH activity have been identified, and some potent JH mimics have been used as insecticides. Recent studies on the enzymes in JH biosynthetic and metabolic pathways should be helpful for the discovery of more potent analogs and for the establishment of new means of pest management using recombinant DNA technology. © Pesticide Science Society of Japan Keywords: juvenile hormone (JH), insect metamorphosis, insect growth regulators, biosynthesis and metabolism of JH. Review* To whom correspondence should be addressed. E-mail: chieka_minakuchi@yahoo.com © Pesticide Science Society of Japan doptera. 17,18) Higher Diptera such as D. melanogaster and the blowfly Calliphora vomitoria produce JH III bisepoxide. 19,20) A small amount of methyl farnesoate, a precursor of JH III, was found in cockroach embryos and larvae. [20][21][22] Methyl farnesoate has also been identified in crustaceans 23) and is thought to have a JH-like action in female reproduction. 24)12Ј-OH JH III identified from the corpora allata of the African locust Locusta migratoria migratorioides was reported to exhibit JH activity when a high dose of this compound was topically applied to Tenebrio pupae. 25,26) Biosynthesis, Transport and Metabolism of Juvenile HormoneIn insects, JH is synthesized in the corpora allata via the mevalonate pathway (Fig. 2).27) The mevalonate pathway also exists in mammals and plants, and the early steps from acetylCoA to farnesyl diphosphate are conserved among these organisms. Importantly, insects and other arthropods do not synthesize cholesterol de novo but have to acquire it from dietary sources because they lack the genes encoding squalene synthase and other subsequent enzymes of the sterol branch. 28,29) Another peculiarity of the mevalonate pathway in insects is the capacity to synthesize JH via the isoprenoid branch.The genes encoding the enzymes in the mevalonate pathway from acetyl-CoA to farnesyl diphosphate have been identified in the genome of D. melanogaster and the malaria mosquito Anopheles gambiae, and in an EST library of the pine engraver Ips pini.27) However, it has been difficult to identify the genes encoding enzymes from farnesyl diphosphate to JH

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Section: Biosynthesis Transport and Metabolism Of Juvenile Hormonementioning

confidence: 99%

Insect juvenile hormone action as a potential target of pest management

Minakuchi

Riddiford

2006

J. Pestic. Sci.

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“…Because whole-organism JHE and JH epoxide hydrolase activity and tissue distribution of JHE have not been quantifi ed in other wing-polymorphic insects, the extent to which these morph-specifi c associations in G. fi rmus also occur in other wing-polymorphic species is currently unknown. Both whole-organism JHE and JH epoxide hydrolase activities have been studied in several nonpolymorphic insects (Zera and Zhang 1995;de Kort and Granger 1996;see below).…”

Section: Endocrine Genetics Of Wing Polymorphism In Gryllus Fi Rmusmentioning

confidence: 99%

“…In all juvenile insects studied thus far, including species of Gryllus, a high concentration of JH causes retention of juvenile characteristics by causing a molt from one juvenile stage to another (Zera and Tiebel 1988;Nijhout 1994). Metamorphosis ensues during the last juvenile stage, when JH drops to a very low level due to reduced hormone biosynthesis and increased degradation by JHE (Nijhout 1994;de Kort and Granger 1996). In the adult stage, JH regulates many aspects of reproduction such as the synthesis of yolk proteins and their uptake by the eggs (Wyatt and Davey 1996).…”

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EVOLUTIONARY ENDOCRINOLOGY OF JUVENILE HORMONE ESTERASE: FUNCTIONAL RELATIONSHIP WITH WING POLYMORPHISM IN THE CRICKET,GRYLLUS FIRMUS

Zera

Huang

1999

Evolution

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The existence, nature, and physiological consequences of genetic variation for juvenile hormone esterase (JHE) activity was studied in the wing‐polymorphic cricket, Gryllus firmus. Hemolymph (blood) JHE activity was sixfold lower in nascent short‐winged (SW) females, relative to nascent long‐winged (LW) females during the last juvenile stadium (stage). Morph‐associated genetic variation for JHE activity had two causes, variation in loci: (1) regulating whole‐organism enzyme activity; and (2) controlling the degree to which JHE is secreted into the blood Reduced JHE activity in nascent SW‐selected individuals was associated with reduced in vivo juvenile hormone catabolism. This suggests that variation in JHE activity during juvenile development may have important physiological consequences with respect to the regulation of blood levels of juvenile hormone and consequent specification of wing morph. This is the first definitive demonstration of genetic variation for hormonal metabolism in any insect and a genetic association between hormone metabolism and the subsequent expression of morphological variation (wing morph). However, we have not yet firmly established whether these associations represent causal relationships In contrast to the clear association between JHE activity and wing morph development, we observed no evidence indicating that variation in JHE activity plays any direct or indirect role in causing the dramatic differences in ovarian growth between adult wing morphs. Variation in JHE activity also does not appear to be important in coordinating the development of wing morph with the subsequent expression of reproductive differences between adult morphs. Finally genetic variation for the developmental profiles of JHE activity during juvenile and adult stages are remarkably similar in three Gryllus species. This suggests that genetic correlations between JHE activities during different periods of development, which underlie these activity profiles, have been conserved since the divergence of the three Gryllus species.

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“…They travel to target tissues through the hemolymph via a juvenile hormone (JH) 1 -binding protein, where they serve to modulate development, metamorphosis, and sexual maturation (1). During metamorphosis and larval development, JH titers are strictly regulated through biosynthesis and catabolism (2,3). JH esterase (JHE) and JH epoxide hydrolase are regarded as the enzymes responsible for JH catabolism.…”

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Juvenile Hormone Diol Kinase

Maxwell

Welch

Schooley

2002

Journal of Biological Chemistry

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Manduca sexta juvenile hormone diol kinase (JHDK) catalyzes the conversion of juvenile hormone (JH) diol to JH diol phosphate. JHDK may be the first example of a phosphotransferase directly involved in the catabolism and inactivation of a lipid-soluble hormone. JHDK is an enzyme crucial for secondary metabolism of JH and possesses high specificity and catalytic efficiency for JH diol. In this study, the purification and characterization of native JHDK are described; its enzymatic properties are examined; and its role in cellular JH metabolism is explored. Using a variety of potential substrates, we show that JHDK has a preference for ATP, but will catalyze the formation of JH diol phosphate with GTP as the phosphate donor. JHDK has a nanomolar K m for JH I diol and a low micromolar value for MgATP. JH II and III diols also serve as phosphate acceptors with low micromolar K m , whereas other diol derivatives of terpenoid esters structurally similar to JH metabolites are not phosphorylated. The reaction proceeds via a sequential Bi Bi mechanism. JHDK is active as a homodimer with a subunit molecular mass of 20 kDa. JHDK binds 5-p-fluorosulfonylbenzoyladenosine and is inhibited by micromolar levels of Ca 2؉ .Juvenile hormones (compound 1; see Fig. 7) are sesquiterpenoids produced in the corpora allata of insects. They travel to target tissues through the hemolymph via a juvenile hormone (JH) 1 -binding protein, where they serve to modulate development, metamorphosis, and sexual maturation (1). During metamorphosis and larval development, JH titers are strictly regulated through biosynthesis and catabolism (2, 3). JH esterase (JHE) and JH epoxide hydrolase are regarded as the enzymes responsible for JH catabolism. However, recent studies have identified a hormonal role for JH acid (compound 2; see Fig. 7) (4, 5), suggesting that JHE is more than an inactivating enzyme. Recently, a cytochrome P450 terpenoid hydroxylase was discovered in the corpora allata of Diploptera punctata; this enzyme may play a role in the temporal suppression of JH titer in the cockroach by metabolizing JH III to 12-hydroxy-JH III (6).Most identifications of JH metabolites in the past have involved studies using either hemolymph or whole organisms, making it difficult to distinguish the role of intracellular JH metabolism. Two studies have been conducted using Manduca sexta tissues dissected and maintained in vitro, one with Malpighian tubules (7) and the other with fat body and imaginal discs (8). The classic model for JH metabolism in insects consists of two primary pathways of inactivation: epoxide hydrolysis to form the diol metabolites and ester cleavage to form the acid metabolites. However, there have been many reports indicating very polar JH metabolites (9 -15). We identified and characterized JH diol phosphate (JHDP; compound 11; Fig. 1), one such polar metabolite, and suggested that it is the principal end product of JH I metabolism in M. sexta (11).We isolated and characterized JH diol kinase (JHDK) from the Malpighian tubules o...

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Regulation of JH titers: The relevance of degradative enzymes and binding proteins

Cited by 112 publications

References 113 publications

Insect juvenile hormone action as a potential target of pest management

Insect juvenile hormone action as a potential target of pest management

EVOLUTIONARY ENDOCRINOLOGY OF JUVENILE HORMONE ESTERASE: FUNCTIONAL RELATIONSHIP WITH WING POLYMORPHISM IN THE CRICKET,GRYLLUS FIRMUS

Juvenile Hormone Diol Kinase

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