ULTRASTRUCTURAL-LOCALIZATION OF ADHALIN IN NORMAL MURINE SKELETAL MYOFIBER

The ultrastructural localization of adhalin and its relations to dystr ophin, beta-dystroglycan, and beta-spectrin were studied in normal mur ine skeletal myofibers. The C-terminal peptides of adhalin and beta-dy stroglycan were synthesized based on their cDNAs, and the affinity-pur ified antibodies against these peptides were produced. Single-immunola beling electron microscopy showed that the adhalin was located just in side the muscle plasma membrane or inside the myofiber a short distanc e from the plasma membrane. The adhalin signal was also noted at the s arcoplasmic side of plasmalemmal invaginations or at vesicular structu res in subsarcolemmal areas. Double-immunogold-labeling electron micro scopy disclosed a similar localization of dystrophin, beta-dystroglyca n, and beta-spectrin. The close association of adhalin with dystrophin or beta-dystroglycan was demonstrated by formation of doublets by sig nals of antibodies of adhalin with those of dystrophin or beta-dystrog lycan and was confirmed by statistical analyses. This study demonstrat ed that the location of adhalin is close to that of dystrophin and bet a-dystroglycan at the muscle plasma membrane.