Phosphorothiolate ribozyme against the conserved sequence in V3 loop of HIV-1

Fluorescent-labeled phosphorothiolate DNA-RNA chimeric hammerhead ribozyme (thio-Rz) was synthesized. The ribozyme recognizes relatively conserved sequences in the functionally important region (V3 loop) of envelope protein of HIV-1. The thio-Rz as well as wild-type ribozyme cleaved RNA transcripts (414 base) of V3 region in a dose-dependent manner. After delivery into the cells, both wild-type and thio-Rz were able to be readily detected. The positive signals faded within 12 h in the former case, while they lasted 24 h in the latter case. The inhibitory effect by thio-Rz on cell fusion between envelope-expressing CHO cells and CD4+ cells appeared to be time-dependent, and about 70% of inhibition was seen at 72 h. Possible applications of the ribozyme against HIV-1 infection were discussed.