Figure 5.

Caldesmon transfection prevents cell rounding induced by trypsin treatment. SV80 cells cotransfected with caldesmon and GFP were incubated in serum-free medium and treated with trypsin. Images were captured using fluorescence microscopy to identify transfected cells (A and F) and differential interference contrast optics to follow the changes in cell morphology induced by the treatment (B–E). (A and B) Culture before trypsin treatment; note transfected cell visualized by fluorescence in A. (C–E) Same field after 40, 80, and 120 s of trypsin treatment, respectively. (F) Fluorescence image corresponding to E. Note that the nontransfected cells retract and become round upon trypsin treatment, whereas the caldesmon-transfected cell does not significantly change shape (compare A and F).