HDAC2 and HDAC3 are expressed by cells in the ganglion cell layer (GCL). (A) Nuclei in the GCL and inner nuclear layer (INL) were strongly labeled for HDAC2. HDAC3 labeling was more diffuse, but also labeled cells in the GCL and INL. Scale bar = 25 μm. (B) Sections from control retinas and retinas 3 days after optic nerve crush. High-magnification images of the GCL are shown. Sections were counter-stained with DAPI to highlight nuclei. In control retinas, HDAC2 was localized to nuclei of GCL cells. HDAC3 labeling was principally in the cytoplasm of GCL cells, although some label appeared to be distributed in or around cellular nuclei. In the GCL of crush retinas, HDAC2 remained nuclear (lower left), while HDAC3 labeling was clearly detected in the nuclei of some cells. Scale bar = 5 μm. Photomicrographs of the individual channels of these merged images are shown in additional file 1. (C) Western blot analysis of HDACs 2 and 3 in cytoplasmic (C) and nuclear (N) fractions of control and experimental retinas 3 days after optic nerve crush. A 59 kD band corresponding to HDAC2 was exclusive to the nuclear fractions in both control and crush retinas. The 49 kD band of HDAC3 was present only in the cytoplasmic fraction in the control eyes, but was distributed between both nuclear and cytoplasmic fractions in the crush samples suggesting nuclear translocation of HDAC3 after ONC. Control antibodies for AcH4 (nuclear) and GAPDH (cytoplasmic) are shown to monitor the relative purity of each fraction.