The zebrafish eno2 promoter. The micrograph shows a single confocal plane through the head region of a Tg(eno2:egfp) zebrafish larva at 5 days post-fertilization, illustrating widespread neuronal expression of the eno2 promoter. Rostral is to left, dorsal up. GFP expression appears green; the section was counterstained using a blue nuclear marker to facilitate identification of anatomical landmarks. Key: Tel, telencephalon;. TeO, optic tectum; Ce, cerebellum; MdO, medulla oblongata; SC, spinal cord; L, ocular lens; PRL, photoreceptor layer of retina; IPL inner plexiform layer of retina; GCL ganglion cell layer of retina; TG, trigeminal ganglion; OC, otic capsule; PLLG, posterior lateral line ganglion; LLN, axons of lateral line nerve.