Fig 4.

ATM kinase activity is required for Na- and R-, but not Z-, induced early lytic EBV protein expression. (A and B) AGS-Akata cells were transfected with control, FLAG-Na (A), Z, or R (B) expression plasmids and treated with or without the ATM kinase inhibitor KU55933 (10 μM). At 48 h after transfection, the cells were harvested and Western blot analysis was performed to examine BMRF1, R, and Z lytic protein expression. The asterisk indicates endogenous Z expression (Akata strain), which runs at a higher molecular weight than does transfected Z (B95.8 strain). A long exposure of Z is included to demonstrate R-induced endogenous Z expression. FLAG antibody was used to detect Na expression. β-Actin was used as a loading control. (C) Mutu I cells were treated with ATM inhibitor (10 μM) for 1 h followed by treatment with dimethyl sulfoxide or TGF-β (5 μg/ml). At 18 h postinduction, RNA was isolated from the cells and treated with DNase and RT-PCR was performed using primers to detect BZLF1 or beta-2 microglobulin (B2M) transcripts.