*2.3. Plasmids and rAAV Vectors*

rAAV-FLAG-h*sox9* is derived from pSSV9, an AAV-2 genomic clone [25,26], and carries a FLAG-tagged human *sox9* cDNA under the control of the cytomegalovirus immediate-early (CMV-IE) promoter [23,27–29]. The vectors were packaged using a helper-free, two-plasmid transfection system in 293 cells with the Adenovirus helper plasmid pXX6 and the packaging plasmid pXX2 [18]. The resulting vector preparations were extensively dialyzed and titrated by real-time PCR [18,30,31], averaging 10<sup>10</sup> transgene copies/mL.
