The neurexin superfamily of Caenorhabditis elegans.

The neurexin superfamily is a group of transmembrane molecules mediating cell-cell contacts and generating specialized membranous domains in polarized epithelial and nerves cells. We describe here the domain organization and expression of the entire, core neurexin superfamily in the nematode Caenorhabditis elegans, which is composed of three family members. One of the superfamily members, nrx-1, is an ortholog of vertebrate neurexin, the other two, itx-1 and nlr-1, are orthologs of the Caspr subfamily of neurexin-like genes.

Site-1 protease is required for cartilage development in zebrafish.

gonzo (goz) is a zebrafish mutant with defects in cartilage formation. The goz phenotype comprises cartilage matrix defects and irregular chondrocyte morphology. Expression of endoderm, mesoderm, and cartilage marker genes is, however, normal, indicating a defect in chondrocyte morphogenesis.