Analysis of Virion Structural Components Reveals Vestiges of the Ancestral Ichnovirus Genome

PLoS Pathogens

Patrick Wincker¹  Gabor Gyapay¹  Sylvie Samain¹  Jean-Michel Drezen²  Fabrice Legeai³  Edith Demettre⁴  Serge Urbach⁴  Michel Cusson⁵  Catherine Béliveau⁵  Fasseli Coulibaly⁶  Max Bergoin⁷  Anne-Nathalie Volkoff⁷  Véronique Jouan⁷  François Cousserans⁷  Bertille Provost⁷ 

[1] CEA-GENOSCOPE-Centre National de Séquençage, Evry, France;CNRS UMR 6035, Institut de Recherche sur la Biologie de l'Insecte, UFR des Sciences et Techniques, Université François Rabelais, Parc Grandmont, Tours, France;INRA UMR Bio3P IRISA Equipe Symbiose IRISA-INRIA, Campus de Beaulieu, Rennes, France;Institut de Génomique Fonctionnelle, Plate-forme Protéomique, CNRS UMR 5203, INSERM U661, Université Montpellier 1, Université Montpellier 2, Montpellier, France;Laurentian Forestry Centre, Natural Resources Canada, Québec, Canada;Structural Virology Group, Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia;UMR 1231 INRA - Université Montpellier 2, Biologie Intégrative et Virologie des Insectes, Place Eugène Bataillon, Montpellier, France

关键词: Viral genomics;    Calyx;    Virions;    Ovaries;    Structural proteins;    DNA;    Genomic library screening;    Viral gene expression;   

DOI  :  10.1371/journal.ppat.1000923

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Many thousands of endoparasitic wasp species are known to inject polydnavirus (PDV) particles into their caterpillar host during oviposition, causing immune and developmental dysfunctions that benefit the wasp larva. PDVs associated with braconid and ichneumonid wasps, bracoviruses and ichnoviruses respectively, both deliver multiple circular dsDNA molecules to the caterpillar. These molecules contain virulence genes but lack core genes typically involved in particle production. This is not completely unexpected given that no PDV replication takes place in the caterpillar. Particle production is confined to the wasp ovary where viral DNAs are generated from proviral copies maintained within the wasp genome. We recently showed that the genes involved in bracovirus particle production reside within the wasp genome and are related to nudiviruses. In the present work we characterized genes involved in ichnovirus particle production by analyzing the components of purified Hyposoter didymator Ichnovirus particles by LC-MS/MS and studying their organization in the wasp genome. Their products are conserved among ichnovirus-associated wasps and constitute a specific set of proteins in the virosphere. Strikingly, these genes are clustered in specialized regions of the wasp genome which are amplified along with proviral DNA during virus particle replication, but are not packaged in the particles. Clearly our results show that ichnoviruses and bracoviruses particles originated from different viral entities, thus providing an example of convergent evolution where two groups of wasps have independently domesticated viruses to deliver genes into their hosts.

【 授权许可】

CC BY