title: Triatoma virus structural polyprotein expression, processing and assembly into virus-like particles.
abstract: In contrast to the current wealth of structural information concerning dicistrovirus particle structure, very little is known about their morphogenetic pathways. Here, we describe the expression of the two ORFs encoded by the Triatoma virus (TrV) genome. TrV, a member of the Cripavirus genus of the Dicistroviridae family, infects blood-sucking insects belonging to the Triatominae subfamily that act as vectors for the transmission of Trypanosoma cruzi, the aetiological agent of the Chagas disease. We have established a baculovirus-based model for the expression of the NS (non-structural) and P1 (structural) polyproteins. A preliminary characterization of the proteolytic processing of both polyprotein precursors has been performed using this system. We show that the proteolytic processing of the P1 polyprotein is strictly dependent upon the coexpression of the NS polyprotein, and that NS/P1 coexpression leads to the assembly of virus-like particles (VLPs) exhibiting a morphology and a protein composition akin to natural TrV empty capsids. Remarkably, the unprocessed P1 polypeptide assembles into quasi-spherical structures conspicuously larger than VLPs produced in NS/P1-coexpressing cells, likely representing a previously undescribed morphogenetic intermediate. This intermediate has not been found in members of the related Picornaviridae family currently used as a model for dicistrovirus studies, thus suggesting the existence of major differences in the assembly pathways of these two virus groups.
authors.affiliation: Unidad de Biofísica (CSIC, UPV/EHU), Barrio Sarriena S/N, 48940 Leioa, Bizkaia, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Sánchez-Eugenia
authors.affiliation: Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Darwin 3, 28049 Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Méndez
authors.affiliation: Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal.|Fundación Biofísica Bizkaia, Barrio Sarriena S/N, 48940 Leioa, Bizkaia, Spain.|Unidad de Biofísica (CSIC, UPV/EHU), Barrio Sarriena S/N, 48940 Leioa, Bizkaia, Spain.
authors.forename: Jailson F B
authors.initials: JFB
authors.lastname: Querido
authors.affiliation: Departamento de Bioquímica, Universidade Federal do Rio Grande do Norte, Natal, Brazil.|Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal.
authors.forename: Marcelo Sousa
authors.initials: MS
authors.lastname: Silva
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencia y Tecnología, Universidad del País Vasco (EHU), Barrio Sarriena S/N, 48940 Leioa, Bizkaia, Spain.|Unidad de Biofísica (CSIC, UPV/EHU), Barrio Sarriena S/N, 48940 Leioa, Bizkaia, Spain.
authors.forename: Diego M A
authors.initials: DMA
authors.lastname: Guérin
authors.affiliation: Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Darwin 3, 28049 Madrid, Spain.
authors.forename: José F
authors.initials: JF
authors.lastname: Rodríguez
mesh_terms: D000818:Animals; D002460:Cell Line; D056629:Dicistroviridae / Q000235:genetics*; D016679:Genome, Viral / Q000235:genetics; D020815:Polyproteins / Q000235:genetics*; D014224:Triatoma / Q000235:genetics*; D014349:Trypanosoma cruzi / Q000821:virology; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D020815:Polyproteins; D017361:Viral Nonstructural Proteins; D015678:Viral Structural Proteins