Juvenile hormone (JH) signalling provides vital regulatory functions during insect development via transcriptional regulation of genes critical for the progression of metamorphosis and oogenesis. Despite the importance of JH signalling, the underlying molecular mechanisms remain largely unknown. Our current understanding of the pathway depends on static end-point information and suffers from the lack of time-resolved data. Here, we have addressed the dynamic aspect of JH signalling by monitoring in real time the interactions of insect JH receptor proteins. Use of two tags that reconstitute a functional luciferase when in proximity enabled us to follow the rapid assembly of a JH receptor heterodimer from basic helix-loop-helix/Per-Arnt-SIM (bHLH-PAS) proteins, methoprene-tolerant (Met) and taiman (Tai), upon specific JH binding to Met. On a similar timescale (minutes), the dissociation of Met-Met complexes occurred, again strictly dependent on Met interaction with specific agonist ligands. To resolve questions regarding the regulatory role of the chaperone Hsp90/83 in the JHR complex formation, we used the same technique to demonstrate that the Met-Hsp83 complex persisted in the agonist absence but readily dissociated upon specific binding of JH to Met. Preincubation with the Hsp90 inhibitor geldanamycin showed that the chaperone interaction protected Met from degradation and was critical for Met to produce the active signalling dimer with Tai. Thus, the JH receptor functions appear to be governed by principles similar to those regulating the aryl hydrocarbon receptor, the closest vertebrate homologue of the arthropod JH receptor.

• Klíčová slova
• Hsp90, bHLH-PAS domain, dimerisation, hormone receptor, juvenile hormone,
• MeSH
• juvenilní hormony * metabolismus   MeSH
• ligandy MeSH
• methopren * farmakologie   metabolismus   MeSH
• molekulární chaperony metabolismus   MeSH
• regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• juvenilní hormony * MeSH
• ligandy MeSH
• methopren * MeSH
• molekulární chaperony MeSH

Synthetic compounds that mimic the action of juvenile hormones (JHs) are founding members of a class of insecticides called insect growth regulators (IGRs). Like JHs, these juvenoids block metamorphosis of insect larvae to reproductive adults. Many biologically active juvenoids deviate in their chemical structure considerably from the sesquiterpenoid JHs, raising questions about the mode of action of such JH mimics. Despite the early deployment of juvenoid IGRs in the mid-1970s, their molecular effect could not be understood until recent discoveries of JH signaling through an intracellular JH receptor, namely the ligand-binding transcription factor Methoprene-tolerant (Met). Here, we briefly overview evidence defining three widely employed and chemically distinct juvenoid IGRs (methoprene, pyriproxyfen, and fenoxycarb), as agonist ligands of the JH receptor. We stress that knowledge of the target molecule is critical for using these compounds both as insecticides and as research tools.

• Klíčová slova
• Drosophila, IGR, agonist ligand, bHLH-PAS protein, hormone receptor, juvenile hormone,
• MeSH
• biologická proměna účinky léků   MeSH
• fenylkarbamáty metabolismus   farmakologie   MeSH
• insekticidy chemie   metabolismus   farmakologie   MeSH
• juvenilní hormony agonisté   chemie   farmakologie   MeSH
• ligandy MeSH
• methopren metabolismus   farmakologie   MeSH
• pyridiny metabolismus   farmakologie   MeSH
• rezistence k insekticidům MeSH
• vývojová regulace genové exprese účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• fenoxycarb MeSH Prohlížeč
• fenylkarbamáty MeSH
• insekticidy MeSH
• juvenilní hormony MeSH
• ligandy MeSH
• methopren MeSH
• pyridiny MeSH
• pyriproxyfen MeSH Prohlížeč

Differences in the growth of dorsolongitudinal flight muscles and gonads in 1-28 days old long-winged (macropterous) and short-winged (brachypterous) adults of the firebug (Pyrrhocoris apterus L.) and the resource allocation to these organs were studied by means of total protein analysis. We found predominant allocation of food resources to flight muscles compared to reproductive organs in both macropterous males and females during the first 5 days of adult life. Subsequent histolysis of developed flight muscles coincided with increased total protein content in some reproductive organs. Initiation of intensive food intake after starvation or application of higher dose of methoprene on macropterous adults changed the resource allocation in favour of growth of reproductive organs and induced precocious histolysis of flight muscles. It indicates an involvement of juvenile hormone in wing morph-related differential allocation of resources in the bug. Increased total protein contents in the ovaries and accessory glands of starved macropterous females and males treated with methoprene, respectively, indicate that proteins derived from the methoprene-induced histolysis of the flight muscles are re-utilized for the growth of the reproductive organs. It is the first report of persistence of differential resource allocation to flight muscles and reproductive organs in the wing-polymorphic insects with non-functional macropterism.

• MeSH
• energetický metabolismus fyziologie   MeSH
• Heteroptera metabolismus   MeSH
• hladovění metabolismus   MeSH
• křídla zvířecí anatomie a histologie   MeSH
• methopren metabolismus   farmakologie   MeSH
• ovarium metabolismus   MeSH
• proteiny metabolismus   MeSH
• rozmnožování fyziologie   MeSH
• svaly metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• methopren MeSH
• proteiny MeSH

Besides being a spectacular developmental process, metamorphosis is key to insect success. Entry into metamorphosis is controlled by juvenile hormone (JH). In larvae, JH prevents pupal and adult morphogenesis, thus keeping the insect in its immature state. How JH signals to preclude metamorphosis is poorly understood, and a JH receptor remains unknown. One candidate for the JH receptor role is the Methoprene-tolerant (Met) Per-Arnt-Sim (PAS) domain protein [also called Resistance to JH, Rst (1)JH], whose loss confers tolerance to JH and its mimic methoprene in the fruit fly Drosophila melanogaster. However, Met deficiency does not affect the larval-pupal transition, possibly because this process does not require JH absence in Drosophila. By contrast, the red flour beetle Tribolium castaneum is sensitive to developmental regulation by JH, thus making an ideal system to examine the role of Met in the antimetamorphic JH action. Here we show that impaired function of the Met ortholog TcMet renders Tribolium resistant to the effects of ectopic JH and, in a striking contrast to Drosophila, causes early-stage beetle larvae to undergo precocious metamorphosis. This is evident as TcMet-deficient larvae pupate prematurely or develop specific heterochronic phenotypes such as pupal-like cuticular structures, appendages, and compound eyes. Our results demonstrate that TcMet functions in JH response and provide the critical evidence that the putative JH receptor Met mediates the antimetamorphic effect of JH.

• MeSH
• biologická proměna genetika   MeSH
• hmyzí geny * MeSH
• kukla účinky léků   růst a vývoj   ultrastruktura   MeSH
• larva účinky léků   růst a vývoj   ultrastruktura   MeSH
• messenger RNA analýza   MeSH
• methopren farmakologie   MeSH
• molekulární sekvence - údaje MeSH
• rezistence k insekticidům genetika   MeSH
• RNA interference MeSH
• Tribolium genetika   růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• messenger RNA MeSH
• methopren MeSH

The flightless bug Pyrrhocoris apterus (L.) is polymorphic for both wing length and flight muscle development. The developed flight muscles of macropterous adults of both sexes first enlarge their volume during the first 5 days after adult emergence, but are then histolyzed in all males and females older than 10 and 14 days, respectively. The flight muscles of brachypterous adult males and females are underdeveloped due to their arrested growth. The total protein content of histolyzed dorsolongitudinal flight muscles from 21-day-old macropterous adults of both sexes is lower than that of developed dorsolongitudinal flight muscles in 5-10-days-old macropterous bugs, but substantially higher than the protein content of underdeveloped dorsolongitudinal flight muscles from adult brachypters. Histolyzed dorsolongitudinal flight muscles differ from the developed ones by decreased quantities of 18 electrophoretically separated proteins. Histolysis of developed dorsolongitudinal flight muscles is accompanied by significant decreases in citrate synthase, glyceraldehyde-3-phosphate dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase enzyme activities and an increase in alanine aminotransferase activity, and can be precociously induced by application of a juvenile hormone analogue. This is the first report of flight muscle polymorphism, histolysis of developed flight muscles and its endocrine control in insects displaying non-functional wing polymorphism.

• MeSH
• 3-hydroxyacyl-CoA-dehydrogenasy metabolismus   MeSH
• alanintransaminasa metabolismus   MeSH
• citrátsynthasa metabolismus   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• glyceraldehyd-3-fosfátdehydrogenasy metabolismus   MeSH
• Heteroptera anatomie a histologie   enzymologie   fyziologie   MeSH
• kosterní svaly anatomie a histologie   enzymologie   fyziologie   MeSH
• křídla zvířecí anatomie a histologie   enzymologie   fyziologie   MeSH
• methopren farmakologie   MeSH
• svalové proteiny fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-hydroxyacyl-CoA-dehydrogenasy MeSH
• alanintransaminasa MeSH
• citrátsynthasa MeSH
• glyceraldehyd-3-fosfátdehydrogenasy MeSH
• methopren MeSH
• svalové proteiny MeSH

A series of 8 new juvenogens (3--10) was prepared starting from a pair of isomeric insect juvenile hormone bioanalogues ( and ). The biological activity of the juvenogens -- was tested for their effect on reproduction of the blowfly Neobellieria (Sarcophaga) bullata and for the juvenilizing activity on the termite Prorhinotermes simplex. Results of biological screening are important in structure--activity studies and promising for potential practical application of some of the juvenogens studied, especially against termites.

• MeSH
• Diptera účinky léků   růst a vývoj   MeSH
• estery chemická syntéza   farmakologie   MeSH
• insekticidy chemická syntéza   chemie   farmakologie   MeSH
• Isoptera účinky léků   růst a vývoj   MeSH
• juvenilní hormony chemická syntéza   farmakologie   MeSH
• larva účinky léků   MeSH
• mastné kyseliny chemická syntéza   farmakologie   MeSH
• methopren analogy a deriváty   farmakologie   MeSH
• molekulární mimikry MeSH
• ovarium účinky léků   MeSH
• rozmnožování účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• estery MeSH
• insekticidy MeSH
• juvenilní hormony MeSH
• mastné kyseliny MeSH
• methopren MeSH

Effects of methoprene and 20-hydroxyecdysone on the development and hemagglutination activity (HA) were studied in both sexes of two members of the Culex pipiens complex-anautogenous C. p. quinquefasciatus and autogenous C. p. molestus. Juvenile hormone analogue (methoprene) and 20-hydroxyecdysone caused developmental changes in both mosquito strains. High larval mortality, prolongation of intermolt period in each larval instar and in the pupal stage, and morphological changes in the larval-pupal and pupal-adult transformations were also observed. Developmental changes were accompanied with some differences in the HA. HA was found in both sexes of both experimental mosquito strains. The juvenile hormone analogue used in the larval stage caused significant decrease of HA in the gut of adults of both sexes. On the other hand, 20-hydroxyecdysone decreased HA only in the female gut. Results obtained indicate that HA depends on the sex, the studied organ, and the level of hormones.

• MeSH
• Culex účinky léků   fyziologie   MeSH
• ekdysteron farmakologie   MeSH
• hemaglutinace účinky léků   MeSH
• methopren farmakologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ekdysteron MeSH
• methopren MeSH