The endocrine regulation of insect metamorphosis and the emerging role of microRNAs

Abstract

Event Abstract Back to Event The endocrine regulation of insect metamorphosis and the emerging role of microRNAs Xavier Belles1* 1 Universitat Pompeu Fabra, Institute of Evolutionary Biology, Spain Insect are classified into two groups according to the metamorphosis mode: the hemimetabolans, which hatch as nymphs with a morphology similar to that of the adult and grow progressively until the adult stage; and the holometabolans, which hatch as a larva with a morphology different from that of the adult, then grow through successive molts until the last larval instar, then to the pupae and to the adult. In the 1930 decade, the experiments of Vincent B. Wigglesworth already showed that the endocrine regulation of insect metamorphosis is based on molting hormones, which induce the successive molts, and juvenile hormones which maintain the juvenile character of them. Later, a number of transcription factors have been reported as mediators of the above hormones, as well as a number of target genes that codify for proteins giving the characteristic shape and behaviour of a juvenile or an adult stage. Most of the information available, however, refers to the most derived holometabolan species, especially to the fruitfly Drosophila melanogaster, whereas data on the less modified hemimetabolan species are scarce. Working on the hemimetabolan Blattella germanica (the German cockroach), we have recently found that microRNAs, which are RNAs of ca. 22 nucleotides that play a generally repressing action on mRNA stability and translation, have a key role in metamorphosis. With RNA interference (RNAi), we silenced the expression of dicer-1, a ribonuclease that mediates the maturation of microRNAs. When dicer-1 was silenced in the last nymphal instar, the production of microRNAs was impaired and the cockroaches, instead of molting to the adult stage as controls did, they transformed into gigantic supernumerary nymphs (Gomez-Orte & Belles, PNAS 106: 21678-21682, 2009). These results demonstrated that microRNAs are essential in insect metamorphosis, at least in hemimetabolans. The hypothesis emerging is that particular microRNAs would repress the expression of genes giving nymphal characters in the molt to adult. To test it, we are now working on a number of microRNAs that could be candidates to play such a role, studying their pattern of expression and the influence of the molting hormone and the juvenile hormone on their abundance. Experiments of silencing of those microRNA that might play a role in metamorphosis, studies on the effect of them on predicted targets, and building of networks representing the interaction microRNA/targets in pre-metamorphic and metamorphic stages are also included in our project. In the end, we hope that the results obtained will illuminate the endocrine mechanisms that allowed the evolutionary transition from the ancestral hemimetaboly to the derived holometaboly. Keywords: comparative endocrinology Conference: 25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010. Presentation Type: Conference Presentation Topic: Comparative endocrinology Citation: Belles X (2010). The endocrine regulation of insect metamorphosis and the emerging role of microRNAs. Front. Endocrinol. Conference Abstract: 25th Conference of the European Comparative Endocrinologists. doi: 10.3389/conf.fendo.2010.01.00017 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Xavier Belles, Universitat Pompeu Fabra, Institute of Evolutionary Biology, Barcelona, Spain, xavier.belles@ibe.upf-csic.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Xavier Belles Google Xavier Belles Google Scholar Xavier Belles PubMed Xavier Belles Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.