The CChMVd-HHR was synthesized by overnight in vitro transcription of the PCR products. To avoid cleavage during transcription,a deoxyribonucleotide (5′-CATGGATCTTCATCAGGACACC
GAC-3′), complementary to a part of the HHR [15]was used in the transcription mixture at a concentration of 10 μM. The RNAs obtained were purified by denaturing (7 M urea) 15% polyacrylamide gel electrophoresis(PAGE) and eluted from the gel overnight in 300 mM sodium acetate, pH 5.2 at 4 °C. The RNAs were recovered from the solution by filtration through 0.22 μm diameter micro-filters and precipitation with ethanol. The purified ribozyme was finally resuspended in water and stored at −20 °C.