CHIRALLY-MODIFIED OLIGONUCLEOTIDES AND THE CONTROL OF GENE-EXPRESSION- THE CASE OF L-DNAS AND L-RNAS

The affinity of L-DNAs, L-RNAs and L/D-DNAs for homopurine.homopyrimid ine d.s. D-DNA and s.s. D-RNA was probed by gel electrophoresis and CD spectroscopy. It was found that the L-modified oligomers do not bind to d.s. DNA and to natural RNA that contains all four natural bases. T hus they cannot be used, in general, for the control of gene expressio n according to the antigene and antisense methodologies. Heterochiral complexes with 1:1 stoichiometry and low thermal stability are formed, instead, by homopurinic L-RNA or L/D-DNA and homopyrimidinic L-RNA wi th the W/C complementary natural RNA sequences.