IL-3 growth factor or serum deprivation up-regulates the expression of endogenous JAZ in association with p53 activation and induction of cell death. (A) IL-3–dependent NFS/N1.H7 murine myeloid cells were deprived of IL-3 for various periods of time. (Left top panel) Northern analysis of JAZ's mRNA level was performed using 32P-labeled JAZ cDNA, and GAPDH expression was used for a loading control. Quantitation of JAZ mRNA level by densitometry is displayed relative to that of GAPDH, and the average ratio of JAZ/GAPDH is set to 1.0 at 0 hour upon IL-3 withdrawal (n = 3). (Left bottom panel) Western blot analysis of JAZ's protein level was performed using antibodies against JAZ (JAZ111), p53, and BAX. Tubulin expression was used for a load control. (Right panel) Cell viability was measured by trypan blue exclusion method. (B-C) NFS/N1.H7 or p53-deficient M1 murine myeloid leukemic cells were deprived of IL-3 and/or serum for various periods of time followed by Western blot analysis (left panels) using antibodies against JAZ, p53, BAX, and/or tubulin and the cell viability assay (right panels). Error bars represent standard deviations (n = 3).
