Fig. 4. Cx43 gene expression in regenerating TA. (A) Cross sections of TAs from Cx43^del/+ mice under control conditions and at different days PI (3 or 7 PI) show X-gal-stained cells. (a,b) Under control conditions, cells of the epymisum (a, arrow), myofibers (b.1, arrows) and cells closely associated with myofibers (b, open arrowhead) were X-gal positive. Inset in b shows co-localization of M-cadherin (fluorescence, left panel) and X-gal staining (phase contrast, right panel). (c,d) At 3 days PI (D3 PI) cells adhered (d, arrows) or close to necrotic fibers showed X-gal stained nucleus. (e,f) At day 7 (D7 PI), numerous myofibers (f, arrows) and cells located between myofibers (f, open arrowheads) showed X-gal reactivity. Scale bar: 160 µm (a); 85 µm (b); 100 µm (b.1); 270 µm (c); 70 µm (d); 90 µm (e); 50 µm (f and inset in b). (B) Co-localization of specific cell markers and X-gal staining in normal and regenerating TA of Cx43^del/+ mice. (Left panels) Co-localization of von Willebrand factor (VWF) in control and at 3 days PI (D3 PI); (top right panels) CD14 reactive cells with X-gal staining at D3 PI; (bottom right panels) co-localization of myogenin (Myo) reactive cells with X-gal staining at 5 days PI (D5 PI). Arrows indicate sites of co-localization. Scale bar in left pair of panels: 50 µm (top), 60 µm (bottom). Scale bar in right pair of panels: 30 µm (top), 20 µm (bottom).