Pronephric kidney patterning and structure is normal in osr2 morphants. A–N: In situ hybridization of wild-type (A, C, E, G, I) and osr2 morphant embryos (B, D, F, H, J) using pronephric nephron markers. pax2a (A–F) is expressed in the entire pronephric nephron, ae2 (G and H) and nbc1 (I and J) are expressed in the proximal nephron, trpm7 (K, L) are expressed in the early distal segment and ret1 (M, N) is expressed in the distal segment of the nephron. Embryonic stages are indicated on the corresponding panels. O, P: a6F immunohistochemistry on wild-type (O) and osr2 morphant (P) showing normal expression of Na+/K+-ATPase in the pronephros.