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Fig. 4. FAK immunolabeling in adult Xenopus leg muscle. Cryosections (8 mm) were labeled with R-BTX and subjected to the immunolabeling
protocol. (A-E) FITC-FAK. (F) R-BTX. (A) FAK labeling caps the tips of muscle fibers (filled arrows) as they insert into the tendon at the
MTJ. Labeling decreases dramatically along the edge of the fibers moving away from the junctional area (open arrowheads). (B) A higher
magnification image of a single fiber, showing the MTJ infoldings labeled with FAK at the tip, labeling along the proximal edge of the fiber,
and the decrease in staining further away from the tip. (C) Control in which the primary 2A7 anti-FAK mAb was preincubated with lysate of
SF21 cells expressing FAK cDNA. (D) A low level of FAK immunolabeling (open arrowhead) is observed along the sarcolemma at
extrajunctional regions of the muscle. (E-F) The same low level of FAK labeling along the sarcolemma (E, filled arrows) is observed at the
NMJ (F), but no concentration of FAK is observed. The bright structures in (E-F) are most likely autofluorescence due to satellite cells. |
