FIG. 3.

Cleavage of the Tf1-derived sequence by the RNase H-deficient mutant of Tf1 RT and by MuLV RT. The 5′-end-labeled 365-nt synthetic RNA was incubated as described in Fig. 2 with either wild-type Tf1 RT, the RNase H-deficient Tf1 RT mutant (the D362N mutant), or with MuLV RT. Lane 1, the 365-nt RNA substrate by itself; lane 2, with wild-type Tf1 RT; lane 3, with wild-type Tf1 RT and Mn²⁺; lane 4, with the D362N mutant of Tf1 RT; lane 5, with the D362N mutant of Tf1 RT and Mn²⁺; lane 6, with MuLV RT; lane 7, with MuLV RT and Mn²⁺. The position of the 5′-end-labeled 23-nt synthetic RNA marker is also indicated as in Fig. 2.