Neuralin-1 is a novel Chordin-related molecule expressed in the mouse neural plate

Cysteine-rich repeats (CRs) of the type described in Chordin constitute con served domains present in an expanding family of secreted molecules. These motifs were shown to mediate directly the antagonism of BMP signaling by Ch ordin and play a major role during development. Here we report the cloning and expression pattern of neuralin-1, a new member of the chordin family. T he mouse cDNA was cloned by homology with a human genomic sequence encoding putative CRs. In the human genome, neuralin-1 transcripts are encoded by 8 exons that span a region of at least 80 kilobases located on chromosome Xq 22.1-23. Neuralin-1 is a 333 amino acid protein containing three CRs, two o f them highly similar to the Chordin CRs that bind BMP. Like chordin, neura lin-1 is able to induce secondary axes after mRNA injection in Xenopus embr yos. Interestingly, during late gastrulation, neuralin-1 and chordin presen t distinct and complementary expression patterns in the mouse: neuralin-1 e xpression starts in the neural plate at mid-gastrulation, whereas chordin e xpression at that stage is restricted to the node and midline mesendoderm L ater on, neuralin-1 expression becomes restricted to discrete regions of th e central nervous system and to derivatives of the neural crest cells. Duri ng organogenesis, neuralin-1 presents a broad expression pattern in many ti ssues such as dorsal root ganglia, gut, condensing cartilages of the skelet on and developing hair follicles. (C) 2001 Elsevier Science Ireland Ltd. Al l rights reserved.