A new look at adenovirus splicing.

Adenovirus type 2 RNA splicing events were quantitatively mapped by using deep cDNA sequencing. The majority of the previously identified splice sites were detected. The lack of complete consistency between the present and previous results is because of some sites which were incorrectly mapped in previous studies, such as the splice sites for pVII, pVIII and E3-11.6K. Several previously predicted splice sites such as that for E3-14.5K and E4ORF3/4 were not detected. In addition, several new splice sites were identified. The novel RNAs may code for hitherto undetected proteins or alternatively spliced mRNAs for known proteins. The open reading frames downstream of two novel splice sites, located in the major late transcription unit region, were shown to be highly conserved. Another interesting possibility is that some of them are non-coding RNAs. Finally, the adenovirus mRNA polyadenylation sites were accurately mapped and in some cases shown to be heterogeneous.