Figure 3

Expression of Tg Usp14CA causes functional and structural deficits at the NMJ. (A) Example traces of MEPCs recorded from diaphragms of 4- to 6-week-old wild type, ax ^J, and TgUsp14CA mice. (B) MEPC frequency in wild type (n = 56 endplates, 10 mice), TgUsp14CA (n = 23 endplates, 4 mice), and ax ^J (n = 75 endplates, 10 mice) muscles. (C) MEPC amplitude in wild type (n = 45 endplates, 10 mice), TgUsp14CA (n = 21 endplates, 4 mice) and ax ^J (n = 75 endplates, 10 mice). (D) MEPC decay constant in wild type (n = 42 endplates, 10 mice), TgUsp14CA (n = 17 endplates, 4 mice) and ax ^J (n = 23 endplates, 10 mice) muscles. (E) Evoked EPC amplitudes in wild type (n = 55 endplates, 10 mice), TgUsp14CA (n = 15 endplates, 4 mice) and ax ^J (n = 75 endplates, 10 mice) muscles. (F) Quantal content in wild type (n = 40 endplates, 10 mice), TgUsp14CA (n = 15 endplates, 4 mice) and ax ^J (n = 59 endplates, 10 mice) muscles. (G) qPCR of AChR subunits in the gastrocnemius muscles of 4-week-old wild type and TgUsp14CA mice. Data were normalized to wild type and n = at least 3 mice per genotype. All data in (B)-(G) are shown as mean ± SEM. Symbols represent Mann-Whitney tests compared against wild type and corrected for multiple comparisons with a Bonferonni adjustment. *p < 0.05, **p < 0.01, and ***p < 0.001. (H) Immunostaining of TA muscles from 4-week-old wild type and TgUsp14CA mice. Axons were visualized via expression of YFP (green) under the neuronal Thy1.2 promoter and AChRs were labeled with rhodamine-conjugated α-bungarotoxin (α-BTX, red). White arrows indicate ultra-terminal sprouting and blue arrows indicate axonal and terminal swellings, scale bars = 50 μm. See also Additional file 2.