Fig. 6

Climbing fibers. (A) Schematic presentation of climbing fibers. (B, C) Detection of EGFP in the inferior olive nucleus in the Tg(ptf1a:eGFP) line at 4 dpf (B) and in the adult (C). Lateral view (B) and sagittal section (C), with anterior to the left. EGFP signals were detected directly with laser scanning microscopy or (B) by immunostaining with an anti-EGFP antibody (C). (D) Expression of pou4f1 (brn3a) in the inferior olive nucleus of the adult hindbrain. In situ hybridization of a sagittal section. (E) Staining of a Tg(pou4f1-hsp70l:EGFP) adult brain with the anti-EGFP antibody. EGFP signals were detected in neurons of the inferior olive nucleus (IO, arrowhead) and in their axons (indicated by an arrow). (F–H) Co-staining of the Tg(pou4f1-hsp70l:EGFP) brain with anti-Pvalb7 (magenta) and anti-EGFP (green) antibodies. Sagittal sections at the lateral (F) and mediolateral levels (G, H). Low (F), middle (G), and high (H) magnification views. The pou4f1-hsp70l:EGFP⁺ climbing fibers were detected as bundles in the GCL (arrow, F), reached the PCL and ML (arrows, G, H), and synapsed on the soma (marked by arrowhead) and proximal dendrites of Purkinje cells. (I–L) Detection of pou4f1:EGFP⁺ climbing fibers at larval stages 5 dpf (I) and 7 dpf (J–L). Immunostaining with anti-EGFP antibody (green, I); co-staining with anti-EGFP (green J, L) and zebrin II antibodies (magenta, K, L). Note that pou4f1:EGFP⁺ climbing fibers from the inferior olive nucleus (IO, arrowhead) were detected at 5 dpf (arrows, I); they innervated to the region containing zebrin II⁺ Purkinje cell (arrows) at 7 dpf. Lateral views with anterior to the left. Low (I) and high-magnification views (J–L). The abbreviations are described in Fig. 1. Scale bars: 200 μm (B–E), 100 μm (I), 50 μm (L, F, G), and 20 μm (H).