The crystallographic structure of Triatoma Virus provides new insights into the Dicistroviridae family.

AGUIRRE, J; SQUIRES, G; POUS, J; ROZAS-DENNNIS, G; COSTABEL, M.D; MARTI G. A; BRESSANELLI, S; NAVAZA J; GUERIN, D.M.A.; REY, F, A

Workshop; II International Workshop on Chagas Disease, triatomine vectors, Trypanosoma cruzi, and Triatoma virus.; 2012

Triatoma virus (TrV) is an insect virus that belongs to the Dicistroviridae family and infects several species of triatomine insects, which are popularly named kissing bugs, the vectors for human trypanosomiasis, commonly known as Chagas disease. Dicistroviruses are non-enveloped +ssRNA viruses pathogenic to both beneficial arthropods and insect pests of medical importance, and therefore have drawn considerable attention in the past decade due to their potential use as biological control agents. In the present work we report the crystallographic structure of the TrV capsid at 2.5Å resolution. The structure reveals a number of distinctive features with respect to the capsid of the Cricket Paralysis Virus (CrPV), the only structure available of a virus from this family. These differences are enough to propose the introduction of a new genus (Triatovirus; typespecies: TrV) within the Dicistroviridae family. Indeed, TrV has a more expanded capsid built with fewer residues, presenting crown-like spikes around the 5-fold axes, which are absent in CrPV. Two metal ions block the channels present along the 5-fold axes of the TrV particle. Furthermore, it displays two autoproteolytic motifs necessary for particle maturation at the capsid interior, instead of one in CrPV. Finally, and most importantly, the structure shows the absence of an ordered VP4 protein within mature, infectious TrV particles. Acknowledgments The authors are grateful to Stephane Duquerroy for his valuable help; to the Servicio Nacional de Chagas, Córdoba, Argentina for the gift of T. infestans colonies; and the staff of ID14-1 of the European Synchrotron Radiation Facility (ESRF) for their support. FAR and JN are members of the CNRS, France. GS acknowledges the french Ministère de l?Education Nationale et de la Recherche for a grant. JA is supported by a UPV/EHU contract (UPV-IT-461-07). JP acknowledges EMBO (ALTF 230/2002) and the European Commission (HPMF-CT-2002-01805) for fellowships. During this work, JA performed a 1-month stay at Institut Pasteur (Paris, France) under the supervision of FAR. G.A.M. is a researcher of the CONICET, Argentina, and is partially supported by ANPC-PICT Nº 32618/05, Argentina. D.M.A.G. received support from Bizkaia:Xede, UPV/EHU (IT-461-07), MV- 2012-2-41 from BG, and MICINN (BFU2007-62062), Spain. This work was partially supported by a SECYT-UNS 24/F035 and CYTED 209RT0364 action (RedTrV: www.redtrv.org), both granted to DMAG.