Localization of obscurins in rodent striated muscles.

<p>Adult mouse and rat heart (A-H2) and tibialis anterior (I-N1) muscle sections were analyzed by immunohistochemistry using antibodies specific for obscurins. In accordance with previous studies, obscurins exhibited a striated pattern in both cardiac and skeletal muscles of mouse and rat origin. <b>Cardiac </b><b>Tissue</b>: Obscurins reside in the mouse and rat epicardium (A-A1 and E-E1, respectively; black arrows). In the myocardial layer, obscurins are found at the sarcolemma (B-B1 and G-G1, mouse and rat tissues, respectively; green arrows) and in sarcomeric striations (C-C1 and F-F1, mouse and rat tissues, respectively; light blue arrows). Interestingly, intercalated disks (pink arrows) and the nuclei of cardiomyocytes (black asterisk) are also labeled in both mouse (D-D1) and rat (H-H2) tissues. In addition, obscurins are found within the cells lining the vasculature throughout the heart (B and B2, and F and F2, mouse and rat tissues, respectively; dark blue arrows). <b>Skeletal Muscle </b><b>Tissue:</b> Similar to earlier observations, obscurins localize to myofibrillar striations (light blue arrows) of both mouse (I-I1) and rat (L-L1) tissues. Obscurins are also present at the sarcolemma (J-J1 and M-M1, mouse and rat tissues, respectively; green arrows) and the nuclei of mouse, but not rat, skeletal muscle using the α-ABD antibody (K and K2, black asterisk). Moreover, obscurins are found within the cells lining the walls of the vasculature (dark blue arrow) in both mouse (K-K1) and rat (N-N1) tissue. Images are shown at multiple magnifications to highlight the various immunopositive structures. Scale bars are included in each panel for reference; for details please refer to the relevant section in the Materials and Methods.