EBV-Encoded Proteins Stabilize HIF1 Alpha Figure 4. HIF1A is localized to the nucleus and cytoplasm in LCLs, in contrast to mitogen-activated B-cells. A – Western blotting of cellular subfractions. The membrane was probed with mouse anti-HIF1A and anti-actin antibodies (left panel). Nuclear HIF1A was detected in the lysates of LCL; however, no nuclear signal for HIF1A was detected in mitogen-activated cells. The HIF1A/actin ratio for all the probes was calculated (right panel). B – Immunostaining of LCLs and mitogen-activated cells with mouse anti-HIF1A antibody (green signal). Nuclear DNA is stained in blue. Notice the presence of nuclear HIF1A signal in LCL (panels a and b) and its absence in the mitogen-activated cells (c and d). doi:10.1371/journal.pone.0042072.g004 Figure 5. Expression of HIF1A-responsive genes in EBV-infected and mitogen-activated B-cells and LCLs. Expression of HIF1A- responsive genes, assessed by Q-PCR. CD40+IL4-activated (ABC) and freshly EBV-infected (EBC) B-cells were compared with LCLs. Untreated and cells treated with NiCl2 were compared. Notice that many genes are upregulated in LCL and freshly EBV-infected cells, compared with CD40+IL4-activated B-cells. doi:10.1371/journal.pone.0042072.g005 PLoS ONE | www.plosone.org 6 July 2012 | Volume 7 | Issue 7 | e42072