AIM:To explore whether HDV ribozymes have the abilityto trans-cleave HCV RNA.METHODS:Three HDV genomic ribozymes weredesigned and named RzC1,RzC2 and RzC3.Thesubstrate RNA contained HCV RNA 5’-noncoding regionand 5“-fragment of C region(5”-NCR-C).All theribozymes and HCV RNA 5’-NCR-C were obtained bytranscription in vitro from their DNA templates,and HCVRNA 5’-NCR-C was radiolabelled at its 5’-end.Undercertain pH,temperature,appropriate concentration ofMg~(2+)and deionized formamide,these ribozymes wererespectively or simultaneously mixed with HCV RNA 5’-NCR-C and reacted for a certain time.The trans-cleavage reaction was stopped at different time points,and the products were separated with polyacrylamidegel electrophoresis(PAGE),displayed byautoradiography.Percentage of trans-cleaved productswas measured to indicate the activity of HDV ribozymes.RESULTS:RzC1 and RzC2 could trans-cleave 26 % and21.8 % of HCV RNA 5’-NCR-C under our reactionconditions with 2.5 mol·L~(-1)deionized formamiderespectively.The percentage of HCV RNA 5’-NCR-Ctrans-cleaved by RzC1,RzC2 or combined usage of thethree ribozymes increased with time,up to 24.9 %,20.3 %and 37.3 % respectively at 90 rain point.Almost noproduct from RzC3 was observed.CONCLUSION:HDV ribozymes are able to trans-cleavespecifically HCV RNA at certain sites under appropriateconditions,and combination of several ribozymesaiming at different target sites can trans-cleave thesubstrate more efficiently than using only one of them. AIM: To explore whether HDV ribozymes have the ability to trans-cleave HCV RNA. METHODS: Three HDV genomic ribozymes were designed and named RzC1, RzC2 and RzC3.Thesubstrate RNA contained HCV RNA 5’-noncoding region and 5 “” fragment of C region 5 ’’ - NCR-C). All of the ribozymes and HCV RNA 5’-NCR-C were obtained by vitro in their DNA templates, and HCV RNA 5’-NCR-C was radiolabelled at its 5’-end.Undercertain pH, temperature, appropriate concentration of Mg 2+ and deionized formamide, these ribozymes were both simultaneously mixed with HCV RNA 5’-NCR-C and reacted for a certain time. The trans-cleavage reaction was stopped at different time points, and the products were separated with polyacrylamide gel electrophoresis (PAGE), displayed by autoradiography. Percentage of trans-cleaved products was measured to indicate the activity of HDV ribozymes. RESULTS: RzC1 and RzC2 could be trans-cleave 26% and 21.8% of HCV RNA 5’-NCR -C under our reactionconditions with 2.5 mol·L -1 deionized form amiderespectively.The percentage of HCV RNA 5’-NCR-Ctrans-cleaved by RzC1, RzC2 or combined usage of the thymidine increases with time, up to 24.9%, 20.3% and 37.3% respectively at 90 rain point. Almost noproduct from RzC3 was observed.CONCLUSION: HDV ribozymes are able to trans-cleavespecifically HCV RNA at certain sites under appropriate conditions, and combination of several ribozymesaiming at different target sites can trans-cleave thesubstrate more efficiently than using only one of them.