4 6 diamidine 2 phenylindole dihydrochloride dapi solution

Frozen cardiac tissue was sliced into 5 µm sections using a cryomicrotome (Leica, Wetzlar, Germany). After thawing, slides were fixed with a cooled 1:1 solution of ethanol and acetic acid. After washing with phosphate buffered saline (PBS), the slices were blocked with 8% (w/v) bovine serum albumin (BSA) in PBS for 30 min at RT. Blocked sections were incubated with anti-α-dystroglycan antibody (clone VIA4-1, Merck, Darmstadt, Germany) at a 1:100 dilution in PBS overnight at 4 °C. After washing in PBS, the slices were incubated with goat anti-mouse Alexa Fluor^® 488 conjugate antibody (ThermoFisher Scientific, Waltham, MA, USA) at a concentration of 1:100 in PBS for 1 h at RT. Afterward, the slices were washed and incubated with 1µg/mL 4′,6-Diamidine-2′-phenylindole dihydrochloride (DAPI)-solution (Carl Roth, Karlsruhe, Germany) in BSA/PBS for 5 min at RT. The sections were washed with distilled water and embedded using Mowiol 4-88 (Carl Roth, Karlsruhe, Germany). Image acquisition was performed using the TCS SP8 confocal microscope (Leica, Wetzlar, Germany).

Frozen cardiac tissue was sliced into 5 µm sections and treated as previously described [10 (link)]. Anti-RBM20 antibody (NBP1-91002, Novus Biologicals, Littleton, CO, USA) and Cy3-conjugated anti-rabbit IgG antibody (C2306, Sigma-Aldrich, St. Louis, MO, USA) were used for RBM20 labelling. For nuclear staining, 4’,6-diamidine-2’-phenylindole dihydrochloride (DAPI) solution (Carl Roth, Karlsruhe, Germany) was used. Sections were embedded with Mowiol 4-88 (Carl Roth).