FIGURE 1.

Reverse transcription with 2 mm Mg²⁺ and increasing Zn²⁺ concentrations. A, schematic representation of the primer-template used for assays. Numbers indicate size in nts. B, primers labeled at 5′-end were hybridized to the RNA template and reactions were performed in the presence of 2 mm MgCl₂ and increasing concentrations of ZnCl₂. Reactions were stopped after 1 min or 30 min as indicated and electrophoresed on a 8% denaturing gel. The concentration of ZnCl₂ in reactions was 0.5, 1, 2, 5, 25, 100, 400, 800 μm. Lane M, size marker in nts as indicated; lane 1, no enzyme; lane 2 and 3, 400 μm ZnCl₂ with no MgCl₂ for 1 and 30 min, resp.; lanes 4 and 5, 400 μm ZnSO₄ with no MgCl₂ for 1 and 30 min, resp.; lane Ø, 2 mm MgCl₂ with no ZnCl₂. Positions of the 20 nt primer and full extension products are indicated.