HAMMERHEAD RIBOZYMES THAT SELECTIVELY CLEAVE THE NPY Y1, Y4, AND Y5 RECEPTOR FULL-LENGTH RNA

The concept of exploiting the ribozyme catalytic center for cleaving a specific target RNA transcript was applied to the design of selective ribozymes for the rat Y1, Y4, and Y5 receptor subtypes, Ribozymes sel ective for the neuropeptide Y (NPY) receptor subtypes were designed an d chemically modified. Recognition sites were selected both according to the extent of their sequence homology between the receptor subtypes and according to the localization within single-stranded regions acce ssible for hybridization. Stability of the ribozymes against nucleolyt ic activities was increased by introducing 2'-O-methylribonucleosides and 3'-terminal modifications, such as inverted ends or dideoxynucleos ides. Ribozymes cleaving the full-length rat Y1, Y4 (1200 nt), and Y5 receptor mRNA (2200 nt) were identified. The specificity of the recogn ition sites and the subtype selectivity of the ribozyme-mediated cleav age was demonstrated.