HYBRIDIZATION PROPERTIES OF BASE-MODIFIED OLIGONUCLEOTIDES WITHIN THEDOUBLE AND TRIPLE-HELIX MOTIF

In this review we describe the influence of modified nucleobases in or der to understand the changes they introduce in double and triple heli x forming oligomers with the aim to study their potential therapeutic use in the antisense/antigene/ribozyme field. The hybridization proper ties of the studied modified oligomers depend on the structure of the modified nucleoside, the number of modifications, the selected sequenc e and the location of the modified nucleoside along the sequence. Unfo rtunately, most available information is based on melting point determ ination, eventually CD experiments and only in a few cases on X-ray an d NMR studies which makes it difficult to put forward general rules fo r predicting modified nucleic acid structures. On the other hand, seve ral of the described base modifications allow us to select new oligonu cleotides with improved properties in the different application fields . (C) Elsevier, Paris.