Fig. 5

Neurofilament heavy chain (NFH) localization to the axon terminal is altered in transgenic but not knock-in mice in tibialis anterior. A, C, E, G To evaluate localization of cytoskeletal structural element NFH to the axon terminal, NMJs from tibialis anterior 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 the synaptophysin or α-BTX, respectively. Consistent with the trends seen in pre- and post-synaptic NMJ measurements, transgenic mice showed significantly decreased uNFH localization to the axon terminal (B; p < 0.0001) and pNFH colocalization with terminal (F; p < 0.0001) while knock-in mice did not show changes in either of these measurements (D, H). 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