Structural relationships of low molecular weight viral RNAs synthesized by RNA polymerase III in nuclei from adenovirus 2-infected cells

Abstract

Previous studies have shown that endogenous class III RNA polymerase(s) in nuclei from adenovirus 2-infected cells synthesize virus-coded RNA species which are approximately 200 (V200), 156 (V156), and 140 (V140) nucleotides in length (Weinmann, R., Brendler, T. G., Raskas, H.J., and Roeder, R. G. (1976) Cell 7, 557-566). The V156 nuclear RNA is identical in sequence to the major virus-associated RNA (VA RNA1 or 5.5 S RNA) synthesized in intact cells (Ohe, K., and Weissman, S. M. (1971) J. Biol. Chem. 246, 6991-7009). The V140 RNA contains several components, one of which appears identical to a minor virus-associated RNA (VA RNAII) which is synthesized in infected cells (Mathews), M. B. (1975) Cell 6, 223-229). Thus transcription of the VA RNAI and VA RNAII genes in vitro accurately reflects the in vivo transcription of these genes. The V200 RNA contains all the nucleotide sequences found in V156 RNA plus an additional 38 to 40 nucleotides on the 3' terminus. Transcription of the gene encoding this RNA species terminates within a stretch of 6 deoxythymidylic acid residues which are located 38 nucleotides beyond the predicted termination site for VA RNAI and which are preceded by a GC-rich sequence of nucleotides. These data suggest either that the V200 RNA is a precursor to the VA RNAI or that the RNA polymerase III occasionally reads-through the presumptive VA RNAI gene termination signal and stops at a potentially stronger downstream termination site.