Expression of the novel basic-helix-loop-helix transcription factor cMespoin presomitic mesoderm of chicken embryos

We have identified a novel chicken gene, cMespo, which encodes a basic-heli x-loop-helix (bHLH) protein with sequence homology to a subgroup of bHLH tr anscription factors that have been implicated in somitogenesis. cMespo tran scripts are first found in the primitive streak of gastrulating chick embry os (HH stage 4) and continue to accumulate in presomitic mesoderm (PSM) unt il somite formation has been concluded. cMespo, however, is not expressed w ithin somites or in tailbud mesoderm. The expression domain of cMespo in PS M largely overlaps with delta-1 but spares a region of several prospective somites at the rostral end of PSM in which c-Meso and Cek-8 are expressed. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.