In situ hybridization verification of microarray results and comparison with expression in the developing retina (part I). mRNA for Tubb5 (A–C), Pak1 (D–F), RhoGDIα (G–I), Rad (J–L), Rac1 (M–O), Creb3l3 (P–R), Crem/Icer (S–U), and bHLHB2 (V–X) was detected by in situ hybridization in uninjured control, 3-day post-optic nerve crush and 48 hpf retinal sections. Note that mRNA levels are elevated in the ganglion cell layer (GCL) of Tubb5, Pak1, RhoGDIα, Rad, Rac1, Creb3l3, and Crem/Icer probed sections following nerve crush injury. bHLHB2 is decreased in the GCL following nerve crush injury. Developmentally, Tubb5, Pak1, RhoGDIα, and Creb3l3 are all expressed in the GCL at 48 hpf (arrows in panels C, F, I, and R). Rad and Crem/Icer are not expressed in the retina at 48 hpf (L and U). Rac1 and bHLHB2 are expressed weakly but uniformly in the retina at 48 hpf (O and X). Sense probes for all genes tested gave no specific signal (data not shown).