[Specific control of gene expression by oligonucleotides: from chemistry to clinical aspects]

Oligonucleotides can be synthesized for specific regulation of gene expression within the living cell. The oligonucleotide acts either on messenger RNA (nonsense and ribozyme strategies) or on DNA (triple helix or antigene strategy). This pharmacological approache requires chemically modified oligonucleotides and appropriate vectors. Applications in gene therapy can also be developed using a DNA vector to produce regulator RNA (nonsense, ribozyme, antigene) within the same cells. Early clinical trials are being conducted to determine the therapeutic efficacy of these two approaches.