GENE TARGETING USING AAV VECTORS: MOLECULAR DETERMINANTS GOVERNING AAV VECTOR TRANSDUCTION, SITE SPECIFIC INTEGRATION AND VECTOR-INDUCED GENE CORRECTION

Clinical trials in gene therapy clearly indicate that improvements must be introduced before important results are to be achieved. In particular, the possibility to directly obtain the correction of genetic defects in the patients' DNA still remains a major goal. Should this not be technically feasible and should it be necessary, or more appropriate, to add a normal gene to the diseased cells, it is important that this gene does not integrate randomly in the genome, with the consequent possibility of altering normal gene expression. Both these goals can be met by studying the properties of the adeno-associated virus (AAV), a small virus that is largely present in the population without causing any disease. This virus can integrate its genome into a specific region of human chromosome 19. Additionally, viral vectors derived from the modification of AAV by the insertion of human sequences can integrate into the host cell genome by replacing the corresponding genomic sequences; if these are mutated, they are thus corrected. The purpose of this project is to understand the molecular mechanisms that control these events inside the cells and to discover how these can be exploited to obtain site-specific integration into the patients' DNA or, as an ultimate goal, to correct a genetic defect.