FIGURE 4.

The effect of overexpression of Ac45 or Ac45ΔC on osteoclast formation and osteoclastic bone resorption. A, schematic representation of GFP, Ac45-IRES-GFP, and Ac45ΔC-IRES-GFP constructs. Bone marrow cell derived osteoclasts transduced with GFP (B–D), Ac45-IRES-GFP (E–G), or Ac45ΔC-IRES-GFP (H–J) retroviruses. Transduced cells were seeded on glass coverslips or 96-well culture plates or bone slices in the presence of RANKL and M-CSF. After 7 days on the glass coverslips or the culture dishes, the cells were fixed and processed for confocal analysis (B, E, and H) or TRACP staining (C, F, and I). In 96-well culture plates, TRACP positive OCLs were counted, and no significant difference was observed between all groups (K). The cells on the bone slices were removed after 14 days of culture, and resorptive lacunae were examined by scanning electron microscopy (D, G, and J). Quantitative analysis shows the percentage of bone slice surface occupied by resorption lacunae (L). ^***. p < 0.001.