Selection in vitro of trans-acting genomic human hepatitis delta virus (HDV) ribozymes

In an effort to identify the functional structure as well as new active variants of the trans-acting genomic ribozyme of human hepatitis delta virus (HDV), we applied an in vitro selection procedure. A total of 14 rounds of selection and amplification was repeated and various mutant ribozymes in G10 and G14 pools analyzed. Active ribozymes which were isolated in the present study (from G10 and G14) all possessed conserved bases (that were identified earlier) in the cis-acting molecule. A dominant clone G10-68 variant was accumulated in generation 14. Interestingly, when base substitutions were analyzed in G10-68 variant, we found that this variant appears to be close to antigenome-like HDV ribozyme molecule. Further investigations of G10-68 confirmed that each mutated base was the most appropriate nucleotide at every position of the HDV ribozyme.