IN-VIVO TRANSCRIPTION FROM THE ADENOVIRUS E2 EARLY PROMOTER BY RNA-POLYMERASE-III

We have previously reported that the subgroup C adenovirus E2 early (E 2E) RNA polymerase II promoter can specify efficient in vitro transcri ption by RNA polymerase III. We now show that promoter proximal sequen ces of the E2E transcription unit are also transcribed by RNA polymera se III in nuclei isolated from adenovirus-infected cells. Small E2E RN A species that possessed the same properties as in vitro synthesized R NA polymerase III E2E transcripts were detected in cytoplasmic RNA pop ulations from infected cells by using blotting, primer extension, and RNase protection assays. The 3' termini of these RNAs were mapped to t hymidine-rich sequences typical of RNA polymerase III termination site s. These results demonstrate that a single gene can be transcribed by both RNA polymerase II and RNA polymerase mi in vivo.