O. Heidenreich et al., CORRELATION OF ACTIVITY WITH STABILITY OF CHEMICALLY-MODIFIED RIBOZYMES IN NUCLEI SUSPENSION, ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT, 6(2), 1996, pp. 111-118
Citations number
31
Categorie Soggetti
Medicine, Research & Experimental","Biothechnology & Applied Migrobiology
To examine hammerhead ribozyme activity in the nuclear environment, we
have used nuclei isolated from HTLV-I tax transformed fibroblasts to
evaluate ribozymes targeted against HTLV-I tax RNA. The ribozyme activ
ity in nuclei suspension was strongly dependent on the resistance of t
he particular ribozyme to endogenous nucleases, A ribozyme containing
exclusively 2'-deoxynucleotides in its stems cleaved target RNA by its
catalytic activity in the absence of proteins and caused degradation
in their presence by induction of nuclear RNase H activity. A ribozyme
containing 2'-amino- and 2'-fluoropyrimidine nucleosides in combinati
on with terminal phosphorothioate linkages was significantly more stab
le in nuclei suspension and also exhibited a more than threefold highe
r cleavage efficacy than its unmodified counterpart. The increased res
istance against nuclease degradation is mainly due to terminal phospho
rothioate linkages, suggesting that both 5' and 3'-exonucleases are pr
imarily responsible for the nuclear degradation of oligonucleotides.