Abstract: Oligonucleotides having the general formula, ##STR1## in which B denotes an arbitrary nucleobase,A equals 0 or CH.sub.2 ;X or Z equals O, S, NH or denotes CH.sub.2 whereby X and Z can be the same or different,V and W denote O, S, Se, NH.sub.2 or an alkyloxy residue, or OH or SH whereby V and W can be the same or different in a monomer unit andL is a H atom or a partner of a binding pair andC equals --O--R and R is an alkyl group with at least 1 C atom which may be modified if desired, or it denotes an alkenyl or alkynyl group with at least 2 C atoms which may be modified if desired, whereby the modification consists of a substitution by one or several halogen, cyano, carboxy, hydroxy, nitro or/and mercapto residues, andn is an arbitrary whole number, are stable antisense probes which bind specifically. Such oligonucleotides and polynucleotides may be used for the regulation of gene expression and as pharmaceutical agents.

Abstract: A synthetic catalytic oligonucleotide structure and nucleotides having the general structural formula (I) contains: ##STR1## in which B represents a nucleoside base which is in particular selected from the group comprising adenin-9-yl (A), cytosin-1-yl (C), guanin-9-yl (G), uracil-1-yl (U), uracil-5-yl (.psi.), hypoxanthin-9-yl (I), thymin-1-yl (T) and 2-aminoadenin-9-yl,V in each nucleotide is independently an O or a CH.sub.2 group,X and W can in each nucleotide be the same or different and are independently of each other O, S, NH.sub.2, alkyl or alkoxy groups with 1 to 10, preferably with 1 to 4 carbon atoms,R is hydrogen or a straight-chained or branched alkyl, alkenyl or alkinyl group with 1 to 10 carbon atoms which is substituted, if desired, with halogen, cyano, isocyano, nitro, amino, carboxyl, hydroxyl or/and mercapto groups, and in which in at least one of the nucleotides the residue R in formula (I) is different from hydrogen and is suitable for the cleavage of a nucleic acid target sequence.