Figure 1.

Localization and distribution of obscurin in human EOMs. (A–C) Longitudinal sections of human EOMs immunolabeled with antibodies against obscurin (green in A) and myomesin (red in B; merged in C), arrowheads indicate the M band. (D–I) Adjacent cross-sections of human EOM immunostained with antibodies against obscurin (green in D and G) and laminin (red in E and H; merged images in F and I). Note that obscurin was present in the vast majority of the human EOM myofibers. In a small percentage of myofibers, obscurin was present only subsarcolemally (arrowheads in D–F) or absent (open arrowheads in G–I). (J–R) Longitudinal sections of human EOM are shown. Obscurin (red in K and L) was maintained at the NMJs labeled by ACHRγ (arrowheads, green in J and L) rather than to be enriched, as known from the limb and trunk muscles.¹⁹ (M–R) Obscurin was also maintained (arrowheads, gray in M and O) in the majority of MTJs, but it was increased (open arrowheads, gray in P and R) at some MTJs. MTJs of human EOMs were identified by their localization and typical labeling by laminin (arrowheads, red in N and O, Q and R).