Fig. 3

Gastrocnemius NMJs show significant changes in localization of phosphorylated and unphosphorylated neurofilament heavy chain to the axon terminal in two mouse models of SBMA. (A, C, E, G) To evaluate localization of cytoskeletal structural element NFH to the axon terminal, NMJs from gastrocnemius were stained with α-BTX, synaptophysin, and SMI31 (phospho-NFH) or α-BTX, TUJ1 (BIII-tubulin), and SMI32 (unphospho-NFH) and evaluated for colocalization with synaptophysin or α-BTX, respectively. B, D Both transgenic (trending, p = 0.0618) and knock-in mice (p < 0.0001) showed decreased uNFH localization to the terminal. F, H Both transgenic (p < 0.001) and knock-in (p < 0.01) mice also showed significantly decreased pNFH colocalization with the terminal. Mann–Whitney Test was used to evaluate statistical significance. uNFH Unphosphorylated neurofilament heavy chain; pNFH Phosphorylated neurofilament heavy chain; NTg Non-transgenic; Tg Transgenic; WT Wild-type; KI Knock-in