Non-viral sequences at the 5′ termini of mRNAs derived from virus-sense and virus-complementary sequences of the ambisense RNA segments of rice stripe tenuivirus

The three small segments of the four RNAs of the rice stripe tenuivirus (RSV) genome have an ambisense coding strategy. The mRNA transcripts corresponding to open reading frames for the non-structural protein (NS4) and nucleocapsid protein (N), which are encoded on virus-sense (v) RNA 4 and virus-complementary sense (vc) RNA 3, respectively, were recovered from polysomes of RSV-infected wheat leaves, and their 5′ termini were analysed. The mRNAs derived from both v and vc sequences contained from 10 to 23 non-viral bases at their 5′ termini. Results of nucleotide sequence similarity analyses indicated that these non-viral heterogenous sequences may be derived from host cellular mRNAs. Taken together, these results suggest that the viral mRNA transcription of either v or vc sequences of ambisense segments of RSV is primed by non-viral oligonucleotides in vivo.