Virus-associated RNAs of naturally occurring strains and variants of group C adenoviruses.

We compared the sequences of the virus-associated (VA) RNAs of group C adenoviruses, serotypes 1, 2, 5, and 6, and of three variants of adenovirus type 2 (Ad2) selected for loss of the BamHI restriction site in the VA RNAI gene. In the naturally occurring strains. VA RNAI exists in two forms which differ by two nucleotides: one form is found in Ad2 and Ad6, and the other is found in Ad1 and Ad5. There are three sites of variation in Va RNAII, the Ad1, Ad2, and Ad5 forms each differing from Ad6 VA RNAII at one of the positions. One of the selected variants has a four-base duplication within the BamHI cleavage site, whereas the two others have acquired a VA RNAI sequence indistinguishable from that of Ad5. The findings are interpreted in terms of the secondary structures of the VA RNAs and the interrelationships among the viruses.