DNAH9 localizes exclusively to distal parts of respiratory ciliary axonemes: costaining of human respiratory epithelial cells with antibodies against axonemal ODA heavy chains DNAH9 (green) and DNAH5 (red). DNAH5 localizes along the entire length of the axonemes, within the microtubule-organizing centers, and specific cytosolic compartments. Nuclei were stained with Hoechst 33342 (blue). (A) DNAH9 staining; (B) DNAH5 staining; (C) overlay; and (D) bright-field image.