FIGURE 5.

Effect of arsenic exposure on histone H3K27 tri-methylation. A, histone H3K27 tri-methylation (H3K27-Me3) was increased in BALB/c 3T3 cells by arsenic treatment. B and C, histone H3K27 tri-methylation was inhibited by knockdown of BMI1 (B) or SUZ12 (C) in arsenic-induced transformed BALB/c 3T3 cells. Histone proteins (1 μg) were first resolved by SDS-15% polyacrylamide gel electrophoresis (A, B, or C, right panels) to show the same histone proteins, and then proteins were transferred to membranes for Western blot analysis. The tri-methylation of histone H3 expression was detected with specific antibodies. Total histone H3 was used to verify equal protein loading.