DNA sequences downstream of the adenovirus type 2 fiber polyadenylation site contain transcription termination signals.

The major late transcription unit of adenovirus type 2 (Ad2) terminates in a region near the end of the linear DNA genome at map units 98.2 to 100. Specific 3' ends mapping in the transcription termination region were detected in nuclear but not cytoplasmic RNA isolated at 16 to 18 h postinfection. Using S1 nuclease protection analysis, a major nuclear RNA species with a 3' terminus at map unit 98.9 was detected. With the use of recombinant expression vectors and run-on transcription in isolated nuclei, we demonstrated that the Ad2 sequences from map units 97.1 to 100, inserted into either the 5' or 3' untranslated sequences of the chloramphenicol acetyltransferase gene (cat), terminated transcription in transfected cells. Termination occurred only when the 97.1- to 100-map-unit sequence was in the same direction of transcription as the major late transcript and was not observed with Ad2 sequences upstream of map unit 97.1.