In vitro–differentiated cells from oc/oc+tcirg1 mice are capable of bone resorption. Osteoclasts were cultured from BM cells harvested from WT or oc/oc+tcirg1 mice. In addition, oc/oc+tcirg1 cells were FACS sorted into GFP⁺ and GFP⁻ populations. After culture with M-CSF and RANKL for 6 or 14 days on cortical bone slices, cells were removed and resorption pits were visualized. (A) Examples of bone resorption pits formed by WT, oc/oc+tcirg1–, oc/oc+tcirg1 (GFP⁺)–, and oc/oc tcirg1 (GFP−)–derived osteoclasts after 6 (upper panel) and 14 (lower panel) days. Bar represents 100 μm. For microscope and camera model, see Figure 3B legend. (B) Percentage of bone surface resorbed after 6 (empty bars) or 14 (solid bars) days of culture. Mean ± SD of a triplicate plating is shown.