In vitro selection analysis of trans-acting HDV ribozyme.

In order 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. After 10 generations, a randomized pool of trans-acting ribozymes accumulated in which the secondary structure of each ribozyme confirmed to the pseudoknot model and important bases in single-stranded regions were all conserved. We were surprised that mutated ribozymes derived from genomic sequence were changed to anti-genomic-like sequences. Further investigations of the most active variant confirmed that each mutated base was the most appropriate nucleotide at every position of HDV ribozyme.