title: Genetic analysis of Eclosion hormone action during Drosophila larval ecdysis.
abstract: Insect growth is punctuated by molts, during which the animal produces a new exoskeleton. The molt culminates in ecdysis, an ordered sequence of behaviors that causes the old cuticle to be shed. This sequence is activated by Ecdysis triggering hormone (ETH), which acts on the CNS to activate neurons that produce neuropeptides implicated in ecdysis, including Eclosion hormone (EH), Crustacean cardioactive peptide (CCAP) and Bursicon. Despite more than 40 years of research on ecdysis, our understanding of the precise roles of these neurohormones remains rudimentary. Of particular interest is EH; although it is known to upregulate ETH release, other roles for EH have remained elusive. We isolated an Eh null mutant in Drosophila and used it to investigate the role of EH in larval ecdysis. We found that null mutant animals invariably died at around the time of ecdysis, revealing an essential role in its control. Further analyses showed that these animals failed to express the preparatory behavior of pre-ecdysis while directly expressing the motor program of ecdysis. Although ETH release could not be detected, the lack of pre-ecdysis could not be rescued by injections of ETH, suggesting that EH is required within the CNS for ETH to trigger the normal ecdysial sequence. Using a genetically encoded calcium probe, we showed that EH configured the response of the CNS to ETH. These findings show that EH plays an essential role in the Drosophila CNS in the control of ecdysis, in addition to its known role in the periphery of triggering ETH release.
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile.
authors.forename: Eileen
authors.initials: E
authors.lastname: Krüger
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile.
authors.forename: Wilson
authors.initials: W
authors.lastname: Mena
authors.affiliation: Entomology Department, Cornell University, 5130 Comstock, Ithaca, NY 14850, USA Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77840, USA.
authors.forename: Eleanor C
authors.initials: EC
authors.lastname: Lahr
authors.affiliation: Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA.
authors.forename: Erik C
authors.initials: EC
authors.lastname: Johnson
authors.affiliation: Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile Entomology Department, Cornell University, 5130 Comstock, Ithaca, NY 14850, USA john.ewer@uv.cl.
authors.forename: John
authors.initials: J
authors.lastname: Ewer
mesh_terms: D000483:Alleles; D000818:Animals; D001522:Behavior, Animal; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development*; D057898:Hemizygote; D007267:Injections; D007301:Insect Hormones / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000254:growth & development; D018978:Molting; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism
chemical_list: D007301:Insect Hormones; D009479:Neuropeptides; C058620:crustacean cardioactive peptide; C403307:ecdysis-triggering hormone, Drosophila; C042645:eclosion hormone
keywords: Behavior; Insect; Molting; Neuropeptide; Postembryonic development