RESUMO
The expression of the DD2R gene was studied by in situ hybridization in the fat body (place of the synthesis of enzymes that degrade juvenile hormone) and ovarian follicular cells (place of the synthesis of 20-hydroxyecdysone) in young and sexually mature D. melanogaster females. It was demonstrated that the DD2R gene is expressed in the fat body, and its expression is higher in young females than in sexually mature females. The DD2R gene expression was not detected in ovarian follicular cells.
Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Corpo Adiposo/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Receptores de Dopamina D2/genética , Animais , Dopamina/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Ecdisona/análogos & derivados , Ecdisona/metabolismo , Feminino , Folículo Ovariano/fisiologia , Maturidade SexualRESUMO
In Drosophila females, the precursor of 20-hydroxyecdysone (20E), ecdysone, is synthesized in the ovary follicular cells. Juvenile hormone (JH) is synthesized de novo in the specialized endocrine gland, corpus allatum (CA); JH degradation is carried out by the enzymes synthesized in the fat body (FB). Earlier we have shown that in Drosophila females, dopamine up- or down-regulates 20E and JH levels depending on the developmental stage. The present study focuses on the role of D1- and D2-like receptors in the age-specific regulation of 20E and JH metabolism by dopamine. We show that in Drosophila melanogaster females D1- and D2-like receptor genes (DopR and DD2R accordingly) are expressed in CA and FB, but not in follicular cells. The level of DopR expression in CA is much higher in the young than in the mature females, whereas DD2R expression is much higher in the mature than in the young females. The DopR and DD2R expression patterns in FB are opposite to those observed in CA. In addition, we obtained data suggesting that the age-specific changes of DopR and DD2R expression in FB are under the control of 20E.
Assuntos
Dopamina/metabolismo , Drosophila/metabolismo , Ecdisterona/metabolismo , Hormônios Juvenis/biossíntese , Receptores Dopaminérgicos/metabolismo , Animais , Corpora Allata/metabolismo , Drosophila/crescimento & desenvolvimento , Corpo Adiposo/metabolismo , Feminino , Fertilização , Imuno-Histoquímica , Ovário/metabolismoRESUMO
The effect of tissue-specific suppression of the dopamine D2-like receptor gene (DD2R) in the corpus allatum (CA), the gland that synthesizes juvenile hormone (JH) on the Drosophila melanogaster resistance to heat stress has been studied. A decreased expression of the DD2R gene in the CA has been found to substantially decrease the heat stress resistance of adult transgenic female, but not male, D. melanogaster compared to the control group, this phenomenon being weakly pronounced in juvenile flies. The effect of DD2R activation on the D. melanogaster reproductive function has been estimated. It has been shown that treatment of D. melanogaster with a synthetic specific agonist of DD2R decreases the fertility, the effect being considerably stronger in adult flies than in juvenile ones. It is concluded that the change in the number of DD2Rs in CA or their activation decreases the fitness of Drosophila.
Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Aptidão Genética , Receptores de Dopamina D2/genética , Animais , Corpora Allata/metabolismo , Proteínas de Drosophila/agonistas , Proteínas de Drosophila/metabolismo , Feminino , Fertilidade/genética , Regulação da Expressão Gênica , Hormônios Juvenis/genética , Hormônios Juvenis/metabolismo , Masculino , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/metabolismoRESUMO
In Drosophila, juvenile hormone (JH) is synthesized de novo in the specialized endocrine gland, corpusallatum (CA). Dopamine (DA) controls JH levels by either stimulating or inhibiting its synthesis and degradation depending on the developmental stage. The present study focuses on the role of D2-like receptors in the regulation of JH synthesis by dopamine. We show that D2-like receptors (DD2R) are expressed in CA cells of Drosophila melanogaster females. In addition, the level of JH production was analyzed in D. melanogaster females with decreased DD2R expression in CA (vs. corresponding control flies) by assessing multiple indices of JH synthesis (JH-hydrolyzing activity and stress reactivity of the system of JH metabolism, activity and stress reactivity of the alkaline phosphatase, activity and stress reactivity of the tyrosine decarboxylase). The differential value obtained for each index suggests increased JH production in female flies that downregulate DD2R. Based on these findings, we postulate that the DA inhibiting effect on the JH synthesis in D. melanogaster is mediated at least in part via D2-like receptors.
