PIAS3 and Huntington disease: At 4 and 8 weeks, some dysregulation begins to occur (Figures S2A and S2B), and by 12 weeks, there are statistically significant increases of SENP1, SENP3, and SUMO-1 in R6/2 cortex and of SENP1, SENP6, PIAS3, SUMO-1, and SUMO-2 in R6/2 striatum (Figures 2B and 2C), suggesting that in vivo SUMO-modifying pathways may be perturbed in HD.