Evaluation of 2'-modified oligonucleotides containing 2'-deoxy gaps as antisense inhibitors of gene expression

摘要: We have used a previously described 17-mer phosphorothioate (Monia, B.P., Johnston, J.F., Ecker, D. J., Zounes, M.A., Lima, W.F., and Freier, S.M. (1992) J. Biol. Chem. 267, 19954-19962) for structure-function analysis of 2'-sugar modifications including 2'-O-methyl, 2'-O-propyl, 2'-O-pentyl, 2'-fluoro. These were analyzed hybridization affinity to complementary RNA antisense activity against the Ha-ras oncogene in cells using highly sensitive transactivation reporter gene system. Hybridization demonstrated that all 2'-modified oligonucleotides hybridized with greater than an unmodified 2'-deoxy oligonucleotide rank order being 2'-fluoro > 2'-O-methyl 2'-O-propyl 2'-O-pentyl 2'-deoxy. Evaluation activities uniformly revealed these compounds completely ineffective inhibiting expression. Activity was restored if compound contained stretch at least five residues. This minimum deoxy length correlated perfectly required efficient RNase H activation vitro partially purified mammalian enzyme. chimeric 2'-modified/deoxy phosphorothioates displayed potencies expression, compared uniform phosphorothioate. Furthermore, potency directly given 2' modification it's RNA. results demonstrate importance target action as mechanism by which exert their effects.