Reverse Transcriptase and RNase H: Present in a Murine Virus and in Both Subunits of an Avian Virus

Abstract

Since its discovery, the viral reverse transcriptase has been well characterized in viruses from the avian system (Kacian et al. 1971; Faras et al. 1972; Hurwitz and Leis 1972; Leis and Hurwitz 1972). The enzyme is able to transcribe natural viral RNA quite efficiently, is closely associated with an RNase H (Moelling et al. 1971; Keller and Crouch 1972; Baltimore and Smoler 1972; Leis et al. 1973; Watson et al. 1973) and consists of two polypeptides on SDS-polyacrylamide gels (Kacian et al. 1971). Several reports on the properties of mammalian viral reverse transcriptase are in contrast to these characteristics of the avian enzyme: no RNase activity seemed to be detectable and the ability to transcribe natural RNA seemed to be lost (Abrell and Gallo 1973; Wang and Duesberg 1973; Leis et al. 1973; Verma et al. 1974a).