Selection of Efficient Ribozyme Cleavage Sites in Target RNAs

The identification of cleavage sites for ribozymes within a particular target RNA exclusively on the basis of sequence informatlon often leads to disappointing failures. Even prediction of secondary structures of the target RNA by computer modeling with a more or less exact prediction of single-stranded or loop regions does not guarantee successful cleavage of the target RNA by a synthetic or an expressed ribozyme (1 ). Expensive screening tests with large numbers of individual ribozymes are the result. As an alternative to this trial-and-error approach, we have recently developed a novel strategy for identification of cleavage sites (2 ).