VA RNAs from avian and XXXX adenoviruses: dramatic differences in length, sequence, and gene location.

@entity1 @entity281 @entity9504 @entity2036
@entity1 adenoviruses encode low-molecular-weight RNAs, so-called VA RNAs, which are transcribed by RNA polymerase III. These RNAs are required for an efficient translation of viral mRNAs late after @entity281 . The genes for the VA RNAs in the genome of CELO virus were mapped and characterized. The results showed a number of surprising differences between CELO virus and @entity1 @entity9504 ( @entity9504 ). Thus, the CELO virus genome encoded only one VA RNA species, in contrast to @entity1 @entity9504 , which encoded two distinct species. The VA RNA from CELO virus was much shorter than the @entity9504 VA RNAs (90 nucleotides compared with 160 @entity2036 ), and there existed no detectable primary sequence homology between them. The predicted secondary structure of CELO virus VA RNA was, however, similar to that of the @entity9504 VA RNAs, implying that the folding rather than the primary sequence was the important feature for biological activity. CELO VA RNA also stimulated translation in a transient expression assay, as did the @entity9504 counterparts, albeit with a much lower efficiency. The location of the gene for CELO VA RNA also differed from all previously characterized serotypes, suggesting that the genome organization of avian and @entity1 adenoviruses are different. Finally, termination of CELO VA RNA transcription occurred in a TTATT sequence which is unique as a stop signal for RNA polymerase III transcription.
