Interaction between wheat germ RNA polymerase II and adenovirus 2 DNA. Evidence for two types of stable binary complexes.

Transcription of Adenovirus 2 DNA (Ad 2 DNA) by wheat germ RNA polymerase II in vitro satisfies criteria that have been used to establish that Escherichia coli or coliphage transcription in vitro is initiated at true promoters. (1) Wheat germ RNA polymerase forms highly stable complexes at specific sites on Ad 2 DNA, with a Kassoc of (4--5) X 10(10) M-1. (2) Electron microscopic visualization of enzyme bound to Ad 2 DNA reveals the location of eight strong binding sites, at least five of which appear to correspond to promoters that have been identified in studies of Ad 2 transcription in vivo [Evans, R. M., Fraser, N., Ziff, E., Weber, J., Wilson, M., & Darnell, J.E. (1977) Cell 12, 733--739; Berk, A.J., & Sharp, P.A. (1977) Cell 12, 45--55; Weinmann, R., & Aiello, L. O. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 1662--1666]. (3) Transcription of Ad 2 DNA from preformed complexes with wheat germ polymerase is capable of escaping the action of rifamycin AF/013 and is relatively resistant to polyriboinosinic acid. In addition, our results are consistent with a two-state model for the interaction of wheat germ RNA polymerase with Ad 2 DNA, indicating that the mechansisms of transcription initiation and promoter-site selection in eucaryotes may be very similar to mechanisms elucidated in procaryotic systems.