Hey genes: a novel subfamily of hairy- and Enhancer of split related genesspecifically expressed during mouse embryogenesis

We have identified a novel subfamily of mammalian hairy/Enhancer of split ( E(spl))-related basic helix-loop-helix (bHLH) genes together with a putativ e Drosophila homologue. While hairy/E(spl) proteins are characterized by an invariant proline residue in the basic domain and a carboxyterminal grouch o-binding WRPW motif, our genes encode a carboxyterminal KP<(YRPW)under bar >G sequence and were thus designated as Hev genes (Hairy/E(spl)-related wit h YRPW motif). Furthermore, they bear a unique C-terminal TE(I/V)GAF motif and the characteristic proline is changed in all Hey family members to glyc ine. RNA in situ hybridization analysis revealed specific expression of Hey 1 during development of the nervous system, the somites, the heart and the craniofacial region. Hey2 is similarly expressed in the somites whereas it. shows a complementary expression in the heart, the craniofacial region and the nervous system. The diversity of expression patterns implies unique fu nctions in neurogenesis, somitogenesis and organogenesis. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.