*2.4. Preparation of the rAAV Vectors*

The vectors were generated using pSSV9, a parental AAV-2 genomic clone [46,47]. rAAV-*lacZ* carries the *E. coli* β-galactosidase (*lacZ*) reporter gene, rAAV-FLAG-h*sox9* a 1.7-kb FLAG-tagged human *sox9* (h*sox9*) cDNA sequence, and rAAV-hTGF-β a 1.2-kb human transforming growth factor beta 1 (hTGF-β) sequence, all controlled by the cytomegalovirus immediate-early (CMV-IE) promoter [25,44,45]. Conventional packaging of not self-complementary vectors was performed using helper-free (two-plasmid) transfection in 293 cells with the packaging plasmid pXX2 and adenovirus helper plasmid pXX6 [25,45]. Vector purification was performed using the AAVanced Concentration Reagent [25], and vector titers were monitored using real-time PCR [25,44,45], averaging 1010 transgene copies/mL (~1/500 functional recombinant viral particles).
