Expression of Raldh2. A. Raldh2 is expressed in the membranes overlying the IVth ventricle (*) and dorsal midbrain (arrow) at e3.5. B. Transverse section through rostral hindbrain (dashed line in A) showing roof plate expression. C. Higher magnification of Raldh2 expression (in B) shows Raldh2 in both the mesenchyme (m) and roofplate (rp). D. Expression in the meningeal membranes surrounding the neural tube from e5 (*). E. Transverse section through hindbrain shows expression is concentrated in the meninges. F. Higher magnification of Raldh2 expression in B shows expression through all layers overlying the ventricle. G. Whole embryo at e6.5 with meninges largely removed. H. Transverse section through midbrain (at level indicated by black dashed line in G) shows expression in the oculomotor nucleus. I. Transverse section through caudal hindbrain (at level indicated by white dashed line in G) shows expression in a dorsal neural population. J. Dorsal view of e8 whole embryo with meninges removed shows Raldh2 in restricted parasagittal domains (arrows). K. Dorsal view (same embryo as J) with the cerebellum displaced to reveal dorsal hindbrain expression (arrow).