Primary hippocampal neurons from WT (12 days in vitro) and His6-HA-SUMO1 KI mice (11 days in vitro) were fixed, permeabilised with Triton X-100, and immunolabelled with antibodies against SUMO1 and Map2, as well as DAPI to label nuclei. Representative images are shown of a WT neuron (A) and a His6-HA-SUMO1 KI neuron (B). (C) Graph showing the nuclear anti-SUMO1 labelling intensity of neuronal nuclei from WT and His6-HA-SUMO1 KI mice (WT, N = 2 mice, 28 neurons; His6-HA-SUMO1 KI, N = 4 mice, 56 neurons). The scatter plots show the data from individual cells while the horizontal line shows the mean nuclear anti-SUMO1 intensity from each genotype (WT, 54.8 AU, His6-HA-SUMO1 KI, 35 AU). Scale bar = 10 µm.