Figure 4. Stathmin1 over-expression in neurons causes abnormally pronounced arborization of axon fibers.

(A, B) Immunohistochemical analysis of stathmin1 in the polymorphic layer. Immunohistochemistry of stathmin1 using wild-type mice (A) and Adcyap^−/− mice (B). White arrows indicate varicosities. Bars = 50 µm. (C) The number of stathmin1 positive dot-like fibers in the polymorphic layer were counted (n = 3, ***P = 3.4E⁻¹² compared with wild-type). Error bars represent ±SEM. (D–F) Morphology of hippocampal primary neurons transfected with stathmin1. Over-expression of GFP (D), GFP-stathmin1 (E) or stathmin1 and GFP (F). The neurons over-expressing stathmin1 have abnormally pronounced sprouting of axon fibers. Bars = 50 µm. (G) The number of secondary neurites from axons was increased by over-expression of stathmin1 (GFP; n = 10, GFP-stathmin1; n = 10, ***P = 2.5E⁻⁵, GFP and stathmin1; n = 6, ***P = 0.00022 compared with GFP). Error bars represent ±SEM.