Sciatic nerves from adult rats. Figs. 3A,3B and 3C, show the variation in ATF3 staining (green) and axonal regeneration (neurofilament immunoreactivity-red) in the distal stumps of resected sciatic nerves at 30 dpo. Some nuclei are closely related to regenerating axons; axonal regeneration does not result in immediate downregulation of ATF3. Fig. 3D shows the distal stump from a sciatic nerve which was cut and reanastomosed 30 days previously. Axonal regeneration is extensive and ATF3 expression has declined. Figs. 3E and 3F are in situ hybridization preparations showing the absence of ATF3 mRNA in intact nerve (E) and its upregulation in the distal stump of a resected nerve at 8 dpo (F). Magnification bars = 50 μm.