TABLE 1.

β-Galactosidase activities in tissue lysates^a

Tissue	β-Galactosidase level (ng/mg of protein)
	Control	RRV/FIV
Liver	0.05 ± 0.02	13.1 ± 5.52
Spleen	NDb	0.10 ± 0.05
Kidney	0.05 ± 0.01	0.10 ± 0.03
Lung	ND	0.12 ± 0.10
Heart	ND	0.12 ± 0.04
Muscle	ND	0.11 ± 0.08

^aSystemic administration of RRV/FIV predominantly transduces the liver. Mice were intravenously injected via tail vein with lactose buffer control (n = 5) or 3 × 10⁷ TU of RRV/FIV vector (n = 5). At 3 weeks postinjection, the mice were sacrificed, and the liver, spleen, kidney, lung, heart, and muscle were harvested and assayed for β-galactosidase activities using Galacto-Light. A whole-liver extract has a total of 366.24 ± 26.21 mg of protein, as measured by Lowry assay. Each mouse received 0.4 ml of RRV/FIV vector preparation containing β-galactosidase activity at 2.12 ± 0.05 μg/ml.

^bND, not detected (below limits of sensitivity of assay).