Figure 11

Purkinje plate formation through Purkinje cells remodeling dendrite-like processes towards the pial side in association with a change in Golgi distribution. (A-D) Time-lapse observation of an E10.5-born Purkinje-like cell in an E13.5 normal cerebellar slice (case presented in Additional file 6). Continuous imaging was carried out automatically (using a 10× objective lens) until the end of culture (15.9 h) (B), when the entire structure of this cell was obtained by reconstructing images captured manually at a higher magnification (20×). Initially (0 h) (A), the labeled cell is horizontally oriented with a long axon-like fiber anteriorly (arrows) and a short, slightly thicker process posteriorly (orange arrowhead). During culture, the cell changes its orientation through extension of new processes towards the pial side (arrowheads in (B)). Note that the remodeling of non-axon-like processes from a posterior or ventricular direction to a more pial direction (B) (orange traces in (D)) is accompanied by a somal movement in the same direction (magenta traces in (D)). (E-J) Double or triple immunostaining to depict the position of Golgi in Purkinje cells before and after the formation of the Purkinje plate (PP) in vivo. After forming the PP, Purkinje cells (G, H, J, and upper part of E) had Golgi distributed towards the pial side within dendrite-like processes positive for microtubule-associated protein 2 (MAP2) (J). Prior to forming the PP, Purkinje cells, which oriented either radially (F) or tangentially (I, and lower part of E), had Golgi distributed in a proximal part of the thick axon-like process (tau⁺) (I). Axon-like fibers (arrows) are thinner in the PP cells (G, H) than in tangentially oriented cells (I). Open arrowheads indicate the Golgi apparatus (green in (E, F) and magenta in (G-J)). Open thick arrows indicate dendrite-like processes.