Evidence from UV transcription mapping that late adenovirus type 2 mRNA is derived from a large precursor molecule.

The UV inactivation of labeling of various late adenovirus type 2 mRNA's is as great or greater than the inactivation of labeling of the same sequences that are present in a large primary RNA transcript in the cell nucleus. Thus, the large nuclear adenovirus type 2-specific RNA appears to be the obligatory precursor of cytoplasmic mRNA. The majority of the mRNA's derived from the large precursor apparently require the synthesis of the whole nuclear molecule. A UV-sensitive target necessary for proper processing of all the mRNA's may exist near the end of the transcription unit.