Chr19 enhancer function in the liver. Known promoters, chicken β-actin (CBA), CMV, mini-CMV, U1a, U1b or transthyretin (TTR) were investigated for expression of the α-1 antitrypsin (AAT) or factor 9 (F9) genes after AAV2 transduction of mouse liver. The Chr19 enhancer elements depicted in Figure 1 coupled to the mini-CMV promoter were also evaluated. Balb/C mice were injected with 5 × 1010 (a) or 1 × 1010 particles (b) of AAV/AAT vectors through the tail vein. Six weeks later, the AAT level in the blood was determined. (c) A total of 4 × 1010 particles of AAV2/F9 were injected into the liver through the portal vein. Eight weeks postinjection, the F9 level in the blood was quantitated by ELISA. The results represent averaged data from five mice plus standard deviation. **P<0.01 or *P<0.05 vs the CBA promoter (a) or the Chr19-mini-CMV promoter (c). AAV, adeno-associated virus; ELISA, enzyme-linked immunosorbent assay.