The cDNA sequence of Trichomonas vaginalis virus-T1 double-stranded RNA.

Trichomonas vaginalis virus (TVV) is a nonsegmented double-stranded (ds) RNA virus that infects the pathogenic protozoan T. vaginalis. To study the virus, we cloned the genomic ds RNA of a TVV-T1 isolate and obtained a contiguous 4647-bp cDNA sequence. Two overlapping genes separated by a + 1 reading frame shift were identified on the plus strand but none on the complementary strand RNA in this sequence. The upstream gene probably encodes a 75-kDa capsid protein, and the downstream gene encodes an 86-kDa polypeptide which is probably the viral RNA-dependent RNA polymerase (RDRP). A potential ribosomal slippage heptamer (C CUU UUU) was identified within the 14-nt overlap of the two genes. The genomic organization and RDRP sequence in TVV-T1 exhibit similarity to those of Saccharomyces cerevisiae virus and Leishmania RNA virus, suggesting that these viruses originate from common ancestry, but are only distantly related to Giardia lamblia virus.