Neurons derived in vitro from ES cells express homeoproteins characteristic of motoneurons and interneurons

We have characterized different neuronal subpopulations derived from in vit ro differentiation of embryonic stem (ES) cells using as markers the expres sion of several homeodomain transcription factors. Following treatment of e mbryo-like aggregates with retinoic acid (RA), Pax-6, a protein expressed b y ventral central nervous system (CNS) progenitors is induced. In contrast, Pax-7 expressed in vivo by dorsal CNS progenitors, and erbB3, a gene expre ssed by neural crest cells and irs derivatives, are almost undetectable. CN S neuronal subpopulations generated expressed combinations of markers chara cteristic of somatic motoneurons (Islet-1/2, Lim-3, and HB-9), cranial ;mot oneurons (Islet-1/2 and Phox2b) and interneurons (Lim-1/2 or EN1). Molecula r characterization of neuron subtypes generated from ES cells should consid erably facilitate the identification of new genes expressed by restricted n euronal cell lineages. (C) 1998 Elsevier Science Ireland Ltd. All rights re served.