Antagonistic actions of ecdysone and insulins determine final size in Drosophila.
All animals coordinate growth and maturation to reach their final size and shape. In insects, insulin family molecules control growth and metabolism, whereas pulses of the steroid 20-hydroxyecdysone (20E) initiate major developmental transitions. We show that 20E signaling also negatively controls animal growth rates by impeding general insulin signaling involving localization of the transcription factor dFOXO and transcription of the translation inhibitor 4E-BP. We also demonstrate that the larval fat body, equivalent to the vertebrate liver, is a key relay element for ecdysone-dependent growth inhibition. Hence, ecdysone counteracts the growth-promoting action of insulins, thus forming a humoral regulatory loop that determines organismal size.
Colombani
Julien
J
CNRS/University of Nice-Sophia Antipolis, UMR6543, Parc Valrose, 06108 Nice Cedex 2, France.
Bianchini
Laurence
L
Layalle
Sophie
S
Pondeville
Emilie
E
Dauphin-Villemant
Chantal
C
Antoniewski
Christophe
C
Carré
Clément
C
Noselli
Stéphane
S
Léopold
Pierre
P
D000818:Animals; D049628:Body Size; D003433:Crosses, Genetic; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000254:growth & development* / Q000378:metabolism; D004441:Ecdysterone / Q000502:physiology*; D005216:Fat Body / Q000502:physiology; D019476:Insect Proteins / Q000502:physiology; D007328:Insulin / Q000502:physiology*; D007329:Insulin Antagonists; D007814:Larva / Q000254:growth & development; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004441:Ecdysterone; D019476:Insect Proteins; D007328:Insulin; D007329:Insulin Antagonists; D019869:Phosphatidylinositol 3-Kinases; D014157:Transcription Factors; C060408:Eip74EF protein, Drosophila