(A) TA muscles of adult mice were injected with 5 μg of plasmid pSIREN encoding either scrambled (Scr) or Tid1-targeted shRNA and electroporated in vivo. 5.5 weeks later the muscles were stained with Alexa Fluor 488-conjugated αBTX and anti-Tid1 followed by Alexa Fluor 633-conjugated goat anti-rabbit IgG. Transfected myotubes expressed DsRed-Express. Arrows highlight the NMJs. Scale bar = 50 μm for (A)–(C). (B) A higher dose (12 μg) of Tid1 shRNA causes fragmentation and diffusion of AChR clusters. (C) 10 weeks after electroporation, AChR clusters shrink (arrow) or disappear in transfected myofibers. (D, E) Tid1 knockdown disrupts the function of the NMJ. 5 weeks after electroporation, spontaneous miniature endplate potentials (mEPPs, D) and nerve stimulation-evoked endplate potentials (EPPs, E) were recorded as described in Experimental Procedures.