FIG. 7.

Scheme used to incorporate CDV and (S)-HPMPA into a template strand. The figure shows the method used to incorporate (S)-HPMPA into DNA. MMLV reverse transcriptase was used to add (S)-HPMPA (“H”) and dGMP to a DNA comprising primer P11 annealed to template T17 (Fig. 1). The products were purified and further extended using vaccinia DNA polymerase and four dNTPs. The T17 strand was then degraded with uracil glycosylase, and the (S)-HPMPA-containing strand was purified and annealed to ³²P-labeled primers P17, P18, or P19 (Fig. 1). Molecules containing CDV, and control DNAs, were prepared the same way, except that we omitted the MMLV reverse transcriptase step. We also used different primers and templates to direct the incorporation of CDV and dCMP (Fig. 1).