Inhibition of the DNA polymerase of Rauscher leukemia virus by single-stranded polyribonucleotides.

The DNA polymerase of Rauscher murine leukemia virus is strongly and specifically inhibited by nontemplate, single-stranded polyribonucleotides with either the resident viral RNA, native calf-thymus DNA, or poly[d(A-T)] as templates. These inhibitory homopolymers are apparently bound to the template site of the polymerase, since they interact competitively with the template. The strength of the inhibition depends on the particular homopolymer used: poly(U) > poly(G) >> poly(A) > poly(C). The K(i) for poly(U) was 0.08 mug/ml, which represents an apparent affinity six times greater than that observed for viral RNA. No such inhibition was observed with a highly purified DNA polymerase from mouse embryos or the Escherichia coli enzyme.