Fig. 3.

Downregulations of Cbx2 and 8 impair mammalian axon regeneration in DRG neurons. a, b The mRNA levels of Cbx2 and 8 after their knockdown by constructed shRNA-vectors. Cbx2-shRNA-1 and -2 in a, and Cbx8-shRNA-1 and -2 in b. The results showed that Cbx2 and Cbx8 genes dramatically decreased in DRG neurons after 4 days of the shRNA vectors electroporation (n = 3, *p < 0.05, **p < 0.01). c Representative images of adult DRG neurons expressing NC-GFP, CBX2-shRNA-1, and -2 vectors separately, as indicated, and fixed at DIV4 after electroporation. Neurons were immunostained with Tuj1-1 (red). Knocking down CBX2 with shRNAs in cultured adult DRG neurons significantly inhibited regenerative axon growth from adult DRG neurons. Scale bar, 100 µm. d Representative images of DRG neurons expressing NC-GFP, CBX8-shRNA-1, and 2 vectors separately, as indicated, and fixed at DIV4 after electroporation. Neurons were immunostained with neuronal marker Tuj1-1 antibody (red). Knocking down Cbx8 with shRNAs in cultured adult DRG neurons significantly inhibited regenerative axon growth ability. Scale bar, 100 µm. e The quantification of axon length after knocking down Cbx2 compared with control (n = 470 for control, n = 360 for Cbx2-shRNA-1 and n = 329 for CBX2-shRNA-2) (n = 3 repeats, *p < 0.05). f The quantification of axon lengths after knocking down Cbx8 compared with control (n = 470 for control, n = 318 for Cbx8-shRNA-1, and n = 302 for Cbx8-shRNA-2) (n = 3, *p < 0.05)