CNE1 and CNE9 govern lacZ expression along distinct domains of brain and spinal cord. (A-C) Whole mount views of transgenic mouse embryos expressing the reporter under control of CNE1 at E11.5 (A, B), and E12.5 (C). (F-H) Whole mount views of embryos carrying CNE9 as enhancer of lacZ expression at E11.5 (F-G), and E12.5 (H). (D, I) Transverse sections through the midbrain at the level shown with dotted lines in panels (C) and (H). (D) In the roofplate and dorsolateral part of alar-column of midbrain the CNE1-induced expression is apparent in marginal, mantle, and ependymal layers of neuroepithelium, whereas in medial section of alar- plate/entire basal-plate of midbrain, expression is restricted to the marginal layer. (I) CNE9-driven lacZ expression is present in ventral midline of caudal midbrain, whereas dorsally reporter signal is confined to the dorso-lateral marginal tissue. (E, J) Transverse sections through the spinal cord at the levels shown with dotted lines in the panels (C) and (F). (E) CNE1-generated transgene expression in the spinal cord is confined to the roofplate (RP), progenitors of Dp5, Dp6, Vp0, Vp1 interneurons, and progenitors of V3 interneurons (open arrowheads). (J) CNE9-induced lacZ expression in the spinal cord was present up-to embryonic day E11.5 and was confined to progenitors of motor neurons (pMN). amb, anterior midbrain; drg, dorsal root ganglia; dsnt, dorsal neural tube; hb, hindbrain; di, diencephalon; mb, midbrain; mge, medial ganglionic eminence; mhb, midbrain-hindbrain boundary; sc, spinal cord; tel, telencephalon. MV, mesencephalic vesicle; AP, alar-plate; BP, basal-plate; FP, floorplate.