4 DNA damage response regulates RAG1/2 expression through ATM-FOXO1 | 101 Figure 7. Inhibition of ATM kinase function augments RAG1/2 recombination activity. (A) Schematic depiction of the fluorescent RAG1/2 activity reporter construct. White and grey triangles represent 12-bp spacer RSS and 23-bp spacer RSS, respectively. RAG1/2-mediated inversional recombination results in the formation of a signal joint and the sense orientation of the GFP cassette. (B) Representative FACS plots of A70 (WT) and R2K3 (Rag2-/-) mouse v-Abl cells treated with vehicle (DMSO; upper panels) or treated with 5 mM STI571 for 96h (lower panels). (C) Representative FACS histograms showing GFP expression within RFP-gate (indicative of RAG1/2 activity) in A70 pre-B cells treated for 96h with vehicle (DMSO) (upper left panel) 5 mM KU55933 (upper right panel), 5 mM STI571 (lower left panel) or 5 mM KU55933 + 5 mM STI571 (lower right panel). Percentages of GFP-positive cells are indicated in FACS plots. (D) Bar graph depicting percentages of GFP-positive cells within RFP-gate in A70 pre-B cells treated for 96h with vehicle (DMSO, white bar) or 5 mM KU55933 (black bar). Means ± SEM are shown (n=4, * p<0.05, Mann-Whitney U test). (E) Bar graph depicting percentages of GFP-positive cells within RFP-gate in A70 pre-B cells treated for 96h with 5 mM STI571 (white bar) or 5 mM STI571 + 5 mM KU55933 (black bar). Means ± SEM are shown (n=4, * p<0.05, Mann-Whitney U test).
RkJQdWJsaXNoZXIy MTk4NDMw