Evolutionary mechanisms driving the evolution of a large polydnavirus gene family coding for protein tyrosine phosphatases

BMC Evolutionary Biology

Research Article

Stéphane Dupas¹  Elisabeth Huguet²  Jean-Michel Drezen²  Elfie Perdereau²  Céline Serbielle²  Catherine Dupuy²  François Héricourt³ 

[1] IRD, Institut de Recherche pour le Développement, UR 072, Laboratoire Evolution, Génomes et Spéciation, UPR 9034, Centre National de la Recherche Scientifique (CNRS), 91198 Gif sur Yvette Cedex, France et Université Paris-Sud 11, 91405, Orsay Cedex, France;Institut de Recherche sur la Biologie de l’Insecte, UMR CNRS 7261, Faculté des Sciences et Techniques, Université F. Rabelais, Parc de Grandmont, 37200, Tours, France;Institut de Recherche sur la Biologie de l’Insecte, UMR CNRS 7261, Faculté des Sciences et Techniques, Université F. Rabelais, Parc de Grandmont, 37200, Tours, France;Laboratoire de Biologie des Ligneux et des Grandes Cultures, UPRES EA 1207, Université d'Orléans, 45067, Orléans cedex, France;INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), BP 6759, 45067, Orléans Cedex 2, France;

关键词: Polydnavirus;    Bracovirus;    Protein tyrosine phosphatase;    Gene duplication;    Positive selection;   

DOI  :  10.1186/1471-2148-12-253

 received in 2012-07-18, accepted in 2012-12-11,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundGene duplications have been proposed to be the main mechanism involved in genome evolution and in acquisition of new functions. Polydnaviruses (PDVs), symbiotic viruses associated with parasitoid wasps, are ideal model systems to study mechanisms of gene duplications given that PDV genomes consist of virulence genes organized into multigene families. In these systems the viral genome is integrated in a wasp chromosome as a provirus and virus particles containing circular double-stranded DNA are injected into the parasitoids’ hosts and are essential for parasitism success. The viral virulence factors, organized in gene families, are required collectively to induce host immune suppression and developmental arrest. The gene family which encodes protein tyrosine phosphatases (PTPs) has undergone spectacular expansion in several PDV genomes with up to 42 genes.ResultsHere, we present strong indications that PTP gene family expansion occurred via classical mechanisms: by duplication of large segments of the chromosomally integrated form of the virus sequences (segmental duplication), by tandem duplications within this form and by dispersed duplications. We also propose a novel duplication mechanism specific to PDVs that involves viral circle reintegration into the wasp genome. The PTP copies produced were shown to undergo conservative evolution along with episodes of adaptive evolution. In particular recently produced copies have undergone positive selection in sites most likely involved in defining substrate selectivity.ConclusionThe results provide evidence about the dynamic nature of polydnavirus proviral genomes. Classical and PDV-specific duplication mechanisms have been involved in the production of new gene copies. Selection pressures associated with antagonistic interactions with parasitized hosts have shaped these genes used to manipulate lepidopteran physiology with evidence for positive selection involved in adaptation to host targets.

【 授权许可】

Unknown   
© Serbielle et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.