Cloning Strategies for Catalytic Antisense RNAs

Catalytic antisense RNAs combine two RNA-based strategies for gene suppression: the antisense approach and the ribozyme approach. Like ordinary antisense RNA, catalytic antisense RNAs are characterized by a relatively long stretch of sequences (>30 bases) that are complementary to the target RNA. Similar to engineered ribozymes, they contain, however, an additional functional domain (or a multiple thereof) of a catalytic RNA. In other words, catalytic antisense RNAs associate to their target RNA in the same manner as conventional antisense RNAs, and as a second element of their suppressive function, they induce chemical cleavage of the phosphodiester backbone of their target RNA by the same mechanism as ribozymes. Thus, the main distinction between catalytic antisense RNAs and conventional ribozymes is the size of the antisense regions flanking the catalytic domain, which results in a different cleavage mechanism.