RESUMO
BACKGROUND/PURPOSE: The flagellated protozoon Trichomonas vaginalis that parasitizes the urogenital tract of humans was reported to harbor double-stranded RNA (dsRNA) viruses. These viruses, identified as Trichomonas vaginalis virus (TVV), belong to the genus Trichomonasvirus of the family Totiviridae. Four species, formally recognized by the International Committee on Taxonomy of Viruses (ICTV), have been reported and distinguished by pairwise comparisons of the sequences of genes coding for major capsid protein (CP) and RNA-dependent RNA polymerase (RdRp). METHODS: Reverse transcription polymerase chain reaction (RT-PCR) was used to amplify the complimentary DNA of target virus genes coding for CP and RdRp. Sequence analyses confirmed the identity of the TVV isolates from T. vaginalis cultures. RESULTS: A total of 35 dsRNA viruses were identified from 18 (19%) T. vaginalis isolates. Multiple TVV species were observed in six of the 18 T. vaginalis cultures. Phylogenetic analyses show monophyly in TVV1 and TVV2 whereas TVV3 and TVV4 appear paraphyletic. The phylogeny of Philippine Trichomonasvirus reflects the global distribution of its host. CONCLUSION: This is the first study in the Philippines and one of the two reports worldwide to detect the four TVVs and their concurrent infection in a single T. vaginalis isolate.
Assuntos
Vírus de RNA/química , Vírus de RNA/isolamento & purificação , RNA de Cadeia Dupla , Trichomonas vaginalis/isolamento & purificação , Trichomonas vaginalis/virologia , Proteínas do Capsídeo/genética , Feminino , Genes Virais/genética , Genoma Viral , Humanos , Filipinas , Filogenia , Vírus de RNA/classificação , Vírus de RNA/genética , Análise de Sequência de RNA , Profissionais do Sexo , Totiviridae/química , Totiviridae/classificação , Totiviridae/genética , Totiviridae/isolamento & purificaçãoRESUMO
Analyzing the positions of 2A-like polypeptide cleavage sites in all available genomes of arthropod totiviruses we propose the limits of all ORF1 coding sequences and observed that two proteins previously predicted in infectious myonecrosis virus genome are unique in the arthropod totiviruses group. A putative protein cleavage site upstream the major capsid protein was also identified only in these genomes. In addition, protein models generated using ab initio and threading approaches revealed conserved structures possibly related to formation of viral protrusions and RNA packaging, clarifying the mechanisms involved in the extracellular transmission. These data appoints that the group formed by arthropod totiviruses are sufficient distinctive to be clustered in new genus belonging to the Totiviridae family, in agreement with previous phylogenetic analysis.
