Figure 3. Reverse transcription in reaction mixtures lacking one of the four dNTPs.

(A) For the sequence 5´-GAGTGG-3´ (template 3), expected-length material was obtained in the presence of either all four dNTPs or a mixture lacking dCTP, expected-length material of altered mobility was obtained in a mixture lacking dATP, and only partial-length material was obtained in a mixture lacking either dGTP or TTP. (B) For the sequence 5´-GCGAGGAGTGTG-3´ (template 4), expected-length material was obtained in the presence of all four dNTPs, expected-length material of altered mobility was obtained in a mixture lacking dATP, and only partial-length material was obtained in a mixture lacking dGTP, TTP, or dCTP. Reaction conditions: 100 nM ribozyme, 125 nM template, 125 nM primer, 2 mM dNTPs, 200 mM MgCl₂, pH 8.3, 20°C, 22 hr.