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 TW-TI 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. (C) 1995 Academic Press, Inc.