Role of the subunits of the avian RNA tumor virus reverse transcriptase

The present paper will concentrate on one aspect of the AMV reverse transcriptase, the role of the two subunits. It has been demonstrated by Grandgenett et al. (1973) that the 60,000 dalton subunit (called α) can be separately purified and that α contains the catalytic sites by which the reverse transcriptase copies RNA, copies DNA and degrades the RNA portion of DNA RNA hybrids (ribonuclease H activity). The authors have compared the properties of α with those of αβ (the two subunit complex) and it is concluded that one role of β is to increase the affinity of reverse transcriptase for template primer. They have also identified α as the subunit encoded by viral RNA using temperature sensitive Rous sarcoma virus mutants.