Caracterização molecular dos Orthobunyavirus do grupo C

• Ano de defesa: 2015
• Autor(a) principal: Carla do Amaral Pinto
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - DEPARTAMENTO DE MICROBIOLOGIA; Programa de Pós-Graduação em Microbiologia; UFMG
• Palavras-chave em Português: Microbiologia; Virologia; Orthobunyavirus; Bunyaviridae
• Link de acesso: http://hdl.handle.net/1843/35516

Caraparu (CARV), Apeu (APEUV) and Itaqui (ITQV) are group C arboviruses, member of Bunyaviridae family and Orthobunyavirus genus. These viruses were first isolated in the Brazilian Amazon in the 50s and their human disease is characterized by high fever, muscular pain and photophobia, during 4-5 days. The orthobunyaviruses’ genome is composed of three segments of single-stranded negative-sense RNA named S (~1000 bp), M (~4500 bp) and L (~7000 bp). Group C viruses are potential emergent human pathogens. However, studies involving these viruses are rare and their molecular characteristics are poorly known, which complicates their correct identification and classification. To date, only partial genomic sequences for APEUV and ITQV were characterized and the genetic relationships between them are still poorly known. The aim of this work is to perform the molecular characterization of the group C arboviruses CARV, APEUV and ITQV sequencing their genome segments and use the data to develop a PCR assay to identify and differentiate these three viral strains. It was possible to complete the L segment sequencing for CARV and APEUV and obtain partial sequences for ITQV M and L segments and CARV and APEUV M segment. The characterization of APEUV L segment revealed that the RdRp of this serogroup C member has all conserved regions described for Orthobunyavirus like regions 3 and 4, besides the "cap-snatching" domain originally described for influenza virus. The data show that genetic relationships among the three serogroup C strains (CARV, APEUV and ITQV) are different when the L and M segments are analyzed. The RdRp analysis suggests that CARV and ITQV L segment have a common origin, which is not shared by APEUV L segment. Moreover, polyprotein analysis suggests a common origin for CARV and APEUV M segment, which would not be shared by ITQV M segment. Since the ICTV uses the cross-reactivity in serological tests which recognize the surface glycoproteins as criterion to difining species, a classification based on RdRp sequence, which is the most conserved and best characterized protein within the Orthobunyavirus genus, would be more appropriate.