Fig. 2. Cx45 and Cx43 are expressed in tibialis anterior muscles (TA) and up-regulated during skeletal muscle regeneration. (A) Western blot analysis of Cx45 present in homogenate samples (100 µg protein) of TAs at different days post BaCl₂ injection (PI) (3, 5, 7, 10 and 14) and in HeLa Cx45 transfectants (H) and control (C) muscles. The different patterns of reactive bands in HeLa and C₂C₁₂ cells are due to the differential posttranscriptional modifications of Cx45, which will be described elsewhere. (B) Western blot analysis of Cx43 in aliquots of heart homogenates (H, used as positive control) and of TAs (100 µg) under control conditions and at days 3, 5, 7 or 10 post BaCl₂ injection (PI). The non-phosphorylated (NP) and phosphorylated (P) forms of Cx43 are indicated. Tub: -tubulin levels measured in stripped blots.