Inability of avian myeloblastosis virus RNA-directed DNA polymerase to transcribe poly(rU) due to instability of the oligo(dA): Poly(rU) complex

Abstract

Avian myeloblastosis virus DNA polymerase is unable to transcribe poly(rU). When the random copolymer, poly(rI,rU), is used as template and oligo(dC) 12–18 is used as primer, there is good incorporation of both dCMP and dAMP into product. In contrast, when oligo(dA) 12–18 is used as primer, transcription is poor. This demonstrates that the problem with oligo(dA) as primer is in the initiation of DNA synthesis. This result, together with the observation of Martin and Tinoco that (dA:rU) duplexes are very unstable, suggests that it is the instability of the primer: template complex which results in the lack of transcription of poly (rU).