Initial characterization of MYH9 in the murine kidney. (A) MYH9 immunoblot of lysates separated by SDS-PAGE. The lanes are for mouse podocytes (mPod), mouse mesangial cells (mMC), COS7 cells (which do not express MYH9), and mouse glomerular lysate (mGlom). (B) Screen for proteinuria in adult mouse urine. Shown is one of two gels with urines from 4-month-old mice of the indicated genotype, separated by SDS-PAGE and stained with Coomassie blue. Each lane is for the urine from one mouse, with a BSA standard shown on the left, in 5-fold dilutions. The arrow indicates albumin. For all urine samples, low-molecular-mass proteins of 20 to 25 kDa are visible, but albumin is barely visible (0.04 μg or less). (C) Phenotype of podocyte-specific KO mice. The left graph shows urine albumin/creatinine ratios for 12- and 36-week-old mice. In the next three graphs, for weights and serum creatinine (Scr) and blood urea nitrogen (BUN) levels of 9-month-old mice, there is no significant difference between KO and control mice (all P values are >0.1 by t test).