title: DPP-mediated TGFbeta signaling regulates juvenile hormone biosynthesis by activating the expression of juvenile hormone acid methyltransferase.
abstract: Juvenile hormone (JH) biosynthesis in the corpus allatum (CA) is regulated by neuropeptides and neurotransmitters produced in the brain. However, little is known about how these neural signals induce changes in JH biosynthesis. Here, we report a novel function of TGFβ signaling in transferring brain signals into transcriptional changes of JH acid methyltransferase (jhamt), a key regulatory enzyme of JH biosynthesis. A Drosophila genetic screen identified that Tkv and Mad are required for JH-mediated suppression of broad (br) expression in young larvae. Further investigation demonstrated that TGFβ signaling stimulates JH biosynthesis by upregulating jhamt expression. Moreover, dpp hypomorphic mutants also induced precocious br expression. The pupal lethality of these dpp mutants was partially rescued by an exogenous JH agonist. Finally, dpp was specifically expressed in the CA cells of ring glands, and its expression profile in the CA correlated with that of jhamt and matched JH levels in the hemolymph. Reduced dpp expression was detected in larvae mutant for Nmdar1, a CA-expressed glutamate receptor. Taken together, we conclude that the neurotransmitter glutamate promotes dpp expression in the CA, which stimulates JH biosynthesis through Tkv and Mad by upregulating jhamt transcription at the early larval stages to prevent premature metamorphosis.
authors.affiliation: Department of Entomology, University of Maryland, College Park, MD 20742, USA.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Huang
authors.forename: Ling
authors.initials: L
authors.lastname: Tian
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdou
authors.forename: Di
authors.initials: D
authors.lastname: Wen
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003335:Corpora Allata / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018698:Glutamic Acid / Q000378:metabolism; D007605:Juvenile Hormones / Q000819:agonists / Q000096:biosynthesis*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008675:Metamorphosis, Biological; D008780:Methyltransferases / Q000378:metabolism*; D009154:Mutation; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018698:Glutamic Acid; D007605:Juvenile Hormones; D008780:Methyltransferases; D017346:Protein Serine-Threonine Kinases; D011956:Receptors, Cell Surface; D016194:Receptors, N-Methyl-D-Aspartate; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; C102117:Br protein, Drosophila; C112506:MAD protein, Drosophila; C064196:dpp protein, Drosophila; C530958:juvenile hormone acid O-methyltransferase, Drosophila; C090169:tkv protein, Drosophila