Measurement of Ribozyme Activity Using RNase Protection

A number of different approaches may be taken to show the effects of ribozymes in cells, yet they all have shortcomings. One major difficulty is that the concentration of target RNAs in cells is often very low. This is confounded by the fact that the cleavage products are generally degraded very quickly after the ribozyme has cut the target. Thus, very sensitive methods are needed to show that the target RNA is actually being cut inside a cell. An easier way to show the effects of ribozymes is simply to monitor the effects on cell phenotype, such as loss of the encoded protein (1 ) or inability of the cell to make infectious virus (2 ,3 ). However, these effects may be owing, at least in part, to antisense activity or some other effect, and do not yield any measurement of the efficiency of RNA cleavage.