Bone marrow progenitor cells from ArKO mice have deficient formation of early osteoblast precursors (CFU-F) and committed osteoblasts (CFU-Ob), but normal osteoclasts maturation (CFU-Oc).

Ex vivo differentiation of primary bone marrow cells from WT (top row) and ArKO (bottom row) animals. Colony counts were decreased in alkaline phosphatase stained ArKO marrow on CFU-F (a & c) (95 ± 55/106 WT marrow cells vs. 33 ± 15/106 ArKO marrow cells, p 6 WT marrow cells vs. 18 ± 15 nodules/106 ArKO marrow cells, p < 0.03). However, WT (e) and ArKO (f) mice had a similar number of TRAP positive multinucleated osteoclasts/well (49 ± 37 osteoclasts/well vs. 32 ± 23 osteoclasts/well) (g). The results are representative of 3 independent experiments, each experiment using pooled cells from 2 animals per genotype. Osteoclast images were captured at 10X magnification (Scale bar = 100 μm).