Acanthamoeba castellanii RNA polymerase II transcription in vitro: accurate initiation at the adenovirus major late promoter.

We have developed and characterized an efficient in vitro system from the protozoan, Acanthamoeba castellanii, that accurately initiates transcription from the adenovirus-2 major late promoter (AdMLP). Transcription by A. castellanii RNA polymerase II (pol II) is initiated at the same nucleotide (nt) that is used by HeLa extracts and is dependent upon adenovirus sequences located between nt -51 and the region around the transcription start point (tsp). The results suggest that the A. castellanii transcription factors for pol II which determine the tsp and the promoter elements that they recognize have been functionally conserved during evolution.