FIG 5.

Time course of HIV RT synthesis on the ∼760-nucleotide RNA template used in the PCR-based α complementation assay. Shown is an autoradiogram with extension of a 20-nucleotide 5′-, ³²P-end-labeled DNA primer on the RNA template used for round 1 synthesis by HIV RT (see Fig. 1). Full extension of the primer resulted in a 199-nucleotide product. A DNA ladder with nucleotide size positions is shown on the left. Concentrations of total and free Mg²⁺ and dNTPs are indicated above each lane. Positions of some prominent DNA synthesis pause sites (P) are indicated on the right. Reactions were performed for (1eft to right) 15 s, 30 s, 1 min, 2 min, 4 min, or 8 min under each condition. A no-enzyme control (−E) is also shown. Refer to Materials and Methods for details.