Axonemal and cytoplasmic localization of CCDC39 in the E18 mouse brain. (A-J) Immunohistochemistry with CCDC39 (green) and acetylated tubulin (red) antibodies in the E18 mouse brain. Ccdc39 is expressed in multiciliated choroid plexus epithelium cells, ependymal cells in the medial walls of the foramen of Monro, subcommissural organ, and central aqueducts. (K) SRRF images of CCDC39 in the axoneme. Solid arrowheads indicate expression of CCDC39 within cilia. Open arrowheads indicate CCDC39 expression within developing ependymal cells that are not yet ciliated. LV, lateral ventricle; 3V, third ventricle; FM, foramen of Monro; SCO, subcommissural organ; CA, central aqueduct; CP, choroid plexus; Ep/EP, ependymal cells. Scale bars: 100 µm (A-E), 10 µm (F-J), 1 µm (K).