Figure 1.

Actin-GFP–expressing RAW cells differentiate into osteoclasts. Actin-GFP RAW cells were stimulated daily with RANK-L/M-CSF to induce differentiation. (A) After 8 d, fully differentiated, multinucleated osteoclasts are revealed by TRAP activity (purple stain). (B) Resorption pits (dark purple) formed after 12 d of culture on dentine slices. (C) A single osteoclast is shown with a podosome belt; colocalization of actin-GFP (green) with phalloidin-rhodamine-isothiocyanate (red) is revealed by yellow/orange color.