Figure 4

Altered response to mechanical stimulation in deltoid tuberosity osteoblast cells of Bmp5^clv/ Bmp5^clvmutants. Cultured cells from the indicated sites were subjected to 0- or 24-h cyclic mechanical strain and visualized afterwards by indirect immunofluorescence using antibodies against collagen 1 (osteoblast) or vimentin (fibroblast). After subjection to 24-h strain, most osteoblasts from the deltoid tuberosity of wild-type (wt) mice become spindle-shaped and reorient perpendicular to the strain axis (arrow). In contrast, Bmp5^clvdeltoid tuberosity osteoblasts display a random orientation after mechanical strain. Femur trochanter osteoblasts from wild-type or Bmp5^clvmice both realign after mechanical strain. Deltoid muscle fibroblasts from wild-type or Bmp5^clvmice also respond appropriately to mechanical strain.