title: Ecdysis triggering hormone ensures proper timing of juvenile hormone biosynthesis in pharate adult mosquitoes.
abstract: Juvenile hormones (JHs) are synthesized by the corpora allata (CA) and play a key role in insect development. A decrease of JH titer in the last instar larvae allows pupation and metamorphosis to proceed. As the anti-metamorphic role of JH comes to an end, the CA of the late pupa (or pharate adult) becomes again "competent" to synthesize JH, which would play an essential role orchestrating reproductive maturation. In the present study, we provide evidence that ecdysis triggering hormone (ETH), a key endocrine factor involved in ecdysis control, acts as an allatotropic regulator of JH biosynthesis, controlling the exact timing of CA activation in the pharate adult mosquito. Analysis of the expression of Aedes aegypti ETH receptors (AeaETHRs) revealed that they are present in the CA and the corpora cardiaca (CC), and their expression peaks 4 h before eclosion. In vitro stimulation of the pupal CA glands with ETH resulted in an increase in JH synthesis. Consistent with this finding, silencing AeaETHRs by RNA interference (RNAi) in pupa resulted in reduced JH synthesis by the CA of one day-old adult females. Stimulation with ETH resulted in increases in the activity of juvenile hormone acid methyltransferase (JHAMT), a key JH biosynthetic enzyme. Furthermore, inhibition of IP3R-operated mobilization of endoplasmic reticulum Ca(2+) stores prevented the ETH-dependent increases of JH biosynthesis and JHAMT activity. All together these findings provide compelling evidence that ETH acts as a regulatory peptide that ensures proper developmental timing of JH synthesis in pharate adult mosquitoes.
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Areiza
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
authors.forename: Marcela
authors.initials: M
authors.lastname: Nouzova
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
authors.forename: Crisalejandra
authors.initials: C
authors.lastname: Rivera-Perez
authors.affiliation: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA. Electronic address: noriegaf@fiu.edu.
authors.forename: Fernando G
authors.initials: FG
authors.lastname: Noriega
mesh_terms: D000330:Aedes / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D003335:Corpora Allata / Q000378:metabolism*; D005260:Female; D007301:Insect Hormones / Q000378:metabolism* / Q000494:pharmacology; D007605:Juvenile Hormones / Q000096:biosynthesis*; D007814:Larva / Q000378:metabolism; D008675:Metamorphosis, Biological; D008780:Methyltransferases / Q000378:metabolism; D011679:Pupa / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D034622:RNA Interference
chemical_list: D001896:Boron Compounds; D007301:Insect Hormones; D007605:Juvenile Hormones; D008780:Methyltransferases
keywords: Biosynthesis; Corpora allata; Ecdysis triggering hormone; Juvenile hormone; Mosquito