GENE-THERAPY 1998 - TRANSIENT OR STABLE MINIGENE EXPRESSION AND GENE REPAIR INACTIVATION/

From inherited diseases, Gene Therapy has now extended to acquired dis orders; in addition, it has moved from therapeutic to prophylactic goa ls as illustrated by DNA vaccines. Indeed, Gene Therapy is expected to revolutionize the practice of Medicine. The breakthrough is that ther apeutic benefits can result from transient expression of minigenes tha t have been introduced into patient's somatic cells. Gene expression c assettes, designed for intracellular production of protein and non-cod ing RNA, are thus experimented on a variety of diseases including canc er, cardiovascular ischemia/stenosis, AIDS,... However, although simpl e in principle, minigene expression therapy is still hampered by many problems; there is not yet a single unquestionable case of definitive clinical success. In december 1991, we devised a new approach to Gene Therapy based on somatic cell transfer of premade ssDNA-recombinase nu cleoprotein filaments. Aimed at repairing mutant genes (inherited dise ases) and at inactivating viral or deleterious genes (AIDS/hepatitides , cancer), the idea is to master homologous recombination and substitu te DNA segments from recipient cells or viruses by homologous genomic DNA from wild type (gene repair) or mutant (gene inactivation) origin. In order to avoid unspecific targeting to repetitive chromosomal elem ents and to bypass potential arrests of the strand exchange reaction b y therapeutic bases, we invented dsDNA-cored filaments. Unlike emergin g RNA-DNA oligonucleotides for single-base substitution, these filamen ts offer broad DNA exchange potentialities and may also prove to be in strumental for targeted integration of minigenes.