Fig. 2.
Targeting of the human HPRT locus by AAV vectors, a. Structure of the AAV vectors used and the human locus. The locations of the AAV terminal repeats (TR), exons 2 and 3 of the HPRTgene, Alu repeats O, P, Q and R, and the probe used in Southern analysis are shown. The sequence differences between the wild-type AAV-HPe2/3 and mutant AAV-HPe2/3X vectors are indicated. The positions of relevant restriction sites are depicted in the chromosomal locus. The AAV-HPe2/3X mutation introduces a PvuI or BspCI site, b, Southern blot of genomic DNA from HT-1080 cells and 13 6TG-resistant clones derived from HT-1080 cells transduced with AAV-HPe2/3X, digested with HindIII and probed for HPRT sequences. The positions of size standards are indicated on the right. c, Southern analysis of genomic DNA as in b, but digested with HindIII and PvuI. The mark at 2.2 kb indicates the position of fragments containing the predicted HPRT modification. d. Southern blot of genomic DNA from MHF2 normal fibroblast clones digested with HindIII or HindIII plus BspCI and probed as in b. Two untransduced (MHF2-A and MHF2-B) and four 6TG-resistant clones transduced by AAV-HPe2/3X were analysed.