After DIV 14 PRG3 is mainly found in axons of primary hippocampal neurons. (A) Confocal images of axonal structures from hippocampal neurons stained with anti-PRG3 296 (green) and anti-tau1 (red) reveal that PRG3 is co-localized with these structures. (B) Confocal images of dendritic extensions stained with anti-PRG3 296 (green) and anti-MAP2 (red) show that PRG3 is not localized in dendrites. Scale bar: 10 μm, also applies to A. (C) Analyses of the PRG3 abundance on tau1 and MAP2 positive structures measured as the fluorescence intensity signal. The fluorescence intensity of PRG3 in tau1 positive structures (n = 111) is significantly higher compared to the PRG3 fluorescence intensity in MAP2 positive structures (n = 105) (p < 0.0001).