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. Author manuscript; available in PMC: 2011 May 18.
Published in final edited form as: Cell Cycle. 2010 Apr 15;9(8):1617–1628. doi: 10.4161/cc.9.8.11470

Figure 6. ATM is required for decatenation G2 checkpoint function.

Figure 6

The NHF1hTERT fibroblast line was infected with a retrovirus to express LacZ or ATM shRNA. 38 A. ICRF-193-induced G2 arrest was quantified using the mitotic entry assay (described in Fig. 1 and 2). ATM-depleted cells and LacZ-transduced control cells were incubated with colcemid for 0-6 h with DMSO or 4 μM ICRF-193 and harvested for quantification of mitotic cells by flow cytometry. The average percentages of cells evading the ICRF-193-induced G2 arrest are shown (+sd, n=3). B. Western immunoblot showing expression of ATM, phospho-ATM, topo IIα and topo IIβ in human fibroblasts and lymphoblasts. Cells were treated with 0.1% DMSO (D), 4 μM ICRF-193 (I) or 4 μM etoposide (E) for three hours before harvest. Equal amounts of cell protein were loaded for electrophoretic separation and immunoblot analysis. ICRF-193 induced phosphorylation of ATM in the shLacZ NHDFs, but not the shATM NHDFs.