Optimizing ribozymes for somatic cell gene therapy.

Therapeutic ribozymes are created through a multistep process that requires trial and error. There are few established rules governing ribozyme design, but guidelines are emerging. It is not yet known whether hammerheads and hairpins, the two ribozymes most widely studied as potential gene therapy agents, have the inherent capability to ablate single genes. Their capacity for specificity and selectivity remains to be explored through rigorous experimentation. These experiments require a battery of control molecules, the characteristics of which are outlined here. Methods for completing the steps in the ribozyme development process, from the selection of a target gene to the quantitation of RNA levels, are also presented and discussed.