PIAS4 and glomerulonephritis: Figure 8A shows that PIASy protein was significantly increased at day 6. Immunohistochemical analysis confirmed that PIASy was expressed at a low level in glomeruli before induction, and its expression was dramatically induced at day 6 (Figure 8E). We noticed that PIASy and E12 were upregulated and distributed similarly in glomeruli in the proliferative phase. Moreover, immunohistological analysis revealed that SUMO-1 was also distributed similarly in glomeruli at day 6, suggesting that protein sumoylation was involved in the progression of glomerulonephritis (Figure 8G and H).