Gene transfer and expression in oligodendrocytes under the control of myelin basic protein transcriptional control region mediated by adeno-associated virus

In this study, a rAAV vector carrying a reporter gene, 'humanized' green fluorescent protein (GFP), linked to the transcriptional control region from the myelin basic protein (MBP) gene (a myelin-forming cell-specific gene) was constructed. Transduction of oligodendrocytes was carried out both in vitro and in vivo. The GFP expression was detected for at least 3 weeks in both transduced oligodendrocyte cell line (MOCH-1 cells) and primary cultures of rat oligodendrocytes. Preferential GFP expression in oligodendrocytes was observed in the primary cultures. In contrast, transduction with rAAV carrying the CMV promoter produced stronger GFP fluorescence in various cell types, with the majority of GFP-expressing cells being the astrocytes. Infusion of approximately 6 x 10(9) particles; (2 x 10(5) infectious units) of rAAV-MBP-GFP into mouse brains resulted in the GFP expression specifically in white matter The GFP protein was detected 15 days later by immunostaining, specifically in the oligodendrocytes. No astrocytes were transduced. Our studies suggested that cell types other than neurons in the central nervous system can also be transduced by rAAV using a cell-type-specific transcriptional control region or promoter. The MBP transcriptional control region might be suitable for gene therapy and other neurobiology studies requiring direct targeting to the myelinating cells.