Molecular evolution of the crustacean hyperglycemic hormone family in ecdysozoansReport as inadecuate

Molecular evolution of the crustacean hyperglycemic hormone family in ecdysozoans - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 PISC - Physiologie de l-Insecte : Signalisation et Communication 2 MBCE - Modèles en biologie cellulaire et évolutive 3 Protéines: Biochimie Structurale et Fonctionnelle, Equipe Biogenèse des Peptides Isomères 4 ABICE - Adaptation et Biologie des Invertébrés en Conditions Extrêmes ADMM - Adaptation et diversité en milieu marin

Abstract : Background: Crustacean Hyperglycemic Hormone CHH family peptides are neurohormones known to regulate several important functions in decapod crustaceans such as ionic and energetic metabolism, molting and reproduction. The structural conservation of these peptides, together with the variety of functions they display, led us to investigate their evolutionary history. CHH family peptides exist in insects Ion Transport Peptides and may be present in all ecdysozoans as well. In order to extend the evolutionary study to the entire family, CHH family peptides were thus searched in taxa outside decapods, where they have been, to date, poorly investigated. Results: CHH family peptides were characterized by molecular cloning in a branchiopod crustacean, Daphnia magna, and in a collembolan, Folsomia candida. Genes encoding such peptides were also rebuilt in silico from genomic sequences of another branchiopod, a chelicerate and two nematodes. These sequences were included in updated datasets to build phylogenies of the CHH family in pancrustaceans. These phylogenies suggest that peptides found in Branchiopoda and Collembola are more closely related to insect ITPs than to crustacean CHHs. Datasets were also used to support a phylogenetic hypothesis about pancrustacean relationships, which, in addition to gene structures, allowed us to propose two evolutionary scenarios of this multigenic family in ecdysozoans. Conclusions: Evolutionary scenarios suggest that CHH family genes of ecdysozoans originate from an ancestral two-exon gene, and genes of arthropods from a three-exon one. In malacostracans, the evolution of the CHH family has involved several duplication, insertion or deletion events, leading to neuropeptides with a wide variety of functions, as observed in decapods. This family could thus constitute a promising model to investigate the links between gene duplications and functional divergence.

Author: Nicolas Montagné - Yves Desdevises - Daniel Soyez - Jean-Yves Toullec -



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