ATF3 immunoreactivity in the proximal and distal stumps of severed sciatic nerves in adult rats at 4, 8, 16 and 30 dpo. Figs. 1A,1C,1E and 1G show proximal stumps and Figs. 1B,1D,1F and 1H show distal stumps at corresponding survival times. ATF3 is strongly expressed by many cells in the distal stump at all times after injury but is more weakly expressed in the proximal stump, and by fewer cells. The inset in Fig. 1C shows part of a distal stump photographed at the same settings as the main panel. Note that there is no ATF3 immunoreactivity in the perineurium (P in Fig. 1D) or in intact sciatic nerve (not shown). Magnification bars = 200 μm in A and B; 50 μm in C and H.