RNA viruses may synthesize completely unknown RNAs from their genome.

 In vitro transcription of vesicular stomatitis virus (VSV) had been established several decades ago, and its accuracy has been improved up to the present. This system is based on mRNA synthesis by RNA dependent RNA polymerase of VSV in cell free system. Although it was confirmed that VSV polymerase can synthesize full length mRNA combining 5' terminal modification and 3' poly-A tail, we can additionally detect diverse short RNAs that possess 5' terminal di- or tri- phosphate in its product, which are considered to be incompletely transcribed mRNAs. For many years, scientists have not been interested in such mysterious RNAs. People don't know even whether there is tendency of the pattern of the appearance of those defective RNAs. It is supposed that VSV may synthesize unknown RNAs from its genome RNA, some of which may have significances for the RNA virus propagation. We may call them a novel viral noncoding RNA.