Figure 1. Conditional inactivation of ATM in osteoclasts results in decreased bone mass.

(A) Western blots showing Phosphorylated-ATM (p-ATM) and total ATM in BMMs incubated with (+) or without (−) sRANKL for 5 d. Representative images of 3 independent experiments are shown. (B) Immunoblots of the cell lysates collected from BMMs and osteoclasts (OCL) probed for ATM. (C) X-ray images of the femurs of 9-week-old Ctrl and Atm^Ctsk mice (left panel). Scale bar, 5 mm. The lengths of the femurs collected from 3- and 9-week-old Ctrl and Atm^Ctsk mice are shown (right panel). (D) Reconstructed three-dimensional μCT images of the distal femurs of Ctrl and Atm^Ctsk mice. Scale bar, 500 μm. (E) Bone morphometric analysis of the femurs collected from 3- and 9-week-old Ctrl and Atm^Ctsk mice. BV/TV, bone volume/tissue volume; Tb.Th, trabecular thickness; Tb.N, trabecular number; Tb.Sp, trabecular space. n = 7 and 6 for 3-week-old Ctrl and Atm^Ctskmice, respectively, and n = 5 mice for each genotype at 9 weeks old.