Fig. 1.

Oxidative stress downregulates protein arginine methyltransferase 4 (PRMT4) protein stability. A: time course study of H₂O₂ in murine lung epithelial (MLE12) cells. MLE12 cells were treated with 200 μM H₂O₂ for different time durations. The cell lysates were analyzed with PRMT4 and glycogen synthase kinase 3β (GSK-3β) immunoblotting, and β-actin was used as a loading control. B: the densitometry results of A were plotted. C: concentration course study of H₂O₂ in MLE12 cells. MLE12 cells were treated with diverse concentration of H₂O₂ for 4 h. PRMT4, GSK-3β, and β-actin immunoblotting was conducted. D: the densitometry results of C were plotted. E: MLE12 cells were treated with 200 μM H₂O₂ for 4 h, and total RNA was isolated and analyzed with quantitative RT-PCR. Results are representative of 3 independent experiments. *P < 0.05 or **P ≤ 0.01 vs. corresponding control.