Figure 8.

Expression of recombinant M-protein fragments in differentiating C2C12 cells. C2C12 cells transfected with constructs encoding T7-tagged Mp2–Mp3 (A–D) or Mp9–Mp13 (E) were allowed to differentiate for 2 (E) or 6 (A to D) d, respectively. Subsequently they were stained with T7-tag antibody (A, C, and E) and tetramethylrhodamine-5-isothiocyanate-labeled phalloidin (B) or MpAA259 (D) followed by secondary antibody. Note that most of the expressed Mp2–Mp3 polypeptide associates with myofibrils (arrowheads in A–D). Transfection with Mp9–Mp13 leads to expression of a polypeptide that binds to myofibrils in a periodic manner (arrowheads in E). For details see RESULTS. Magnification, 1050×.