Fig. 4. Analysis of growth rates and urinary protein levels. (A) Growth curves (weight versus age) of control mice, Lamb2^-/- mice and Lamb2^-/- mice carrying transgenes. Lamb2^-/- and Lamb2^-/-; NEPH-B2 mice fail to surpass a weight of 4 g and die at 3-4 weeks of age. By contrast, Lamb2^-/-; MCK-B2 mice grow at a rate similar to controls but die at 1 month of age. Lamb2^-/-; MCK-B2; NEPH-B2 doubly transgenic mice exhibit normal weight gain and a long life. (B) Proteinuria in Lamb2^-/-; MCK-B2 mice. Urine (1 µl) was analyzed by SDS-PAGE and stained with Coomassie Blue. M, markers; the pink band is albumin. Lanes 1, 5 and 6: urine from Lamb2+/-; MCK-B2 mice. Lanes 2, 4 and 7: urine from Lamb2^-/-; MCK-B2 mice. Lane 3 was empty.