Reverse transcriptase mediated binding of primer tRNA to the viral genome

Abstract

A complex between tRNA ^Trp (beef) and 35 S RNA from avian myelo-blastosis virus is obtained when the mixture is preincubated in the presence of reverse transcriptase at 35° C. The tRNA-RNA complex is active in initiating DNA synthesis catalyzed by reverse transcriptase. The interaction of tRNA with reverse transcriptase involves the partial unwinding of the acceptor stem of tRNA, as evidenced by nuclease digestion with RNAase T1 and micrococcal nuclease. When tRNA ^GLu₂ (coli), having a high degree of similarity with primer tRNA at the level of the acceptor stem, was used as primer for DNA synthesis, a low but significant level of incorporation was obtained, if the reaction was performed at 35° C, while a high incor -poration, similar to the one obtained with tRNA ^Trp was obtained when the annealing between tRNA ^Glu₂ and 35 S RNA was performed at 80° C. Our evidences point out to an important role of the viral DNA polynerase in positioning the primer on the RNA genome.