Fig. 4. Higher than normal levels of GAA expression with serotype 1. Diaphragms harvested from 1-month-old Gaa^-/- mice treated in utero with 8.14x10¹⁰ particles of rAAV1-CMV-hGAA (1-8) were assayed for GAA expression by: (A) X-Gluc staining, (B) GAA activity assay and (C) western analysis. Expression levels ranged from nothing to vastly greater than normal. In the western analysis, human placental GAA was included as a positive control, showing predominant isoforms of 95 kDa precursor, and 76 and 67 kDa processed forms, with the arrow indicating the 76 kDa mature form. The unknown species detected at the bottom of the blot serves as a loading control (asterisk).