Expression is localized to the nervous system.
Neuronal and mesodermal cell types are generated in separate cell lineages during the larval development of Caenorhabditis elegans . The gene sem-4 is required in both types of lineages for the normal development of neuronal and mesodermal cell types. The sem-4 gene encodes a protein containing seven zinc finger motifs of the C2H2 class, four of which are arranged in two pairs widely separated in the primary sequence of the protein. The spalt expression domains expand in response to ectopic hedgehog activity and narrow in the presence of protein kinase A activity, an antagonist of hedgehog signaling, indicating that spalt is a hedgehog target gene. Xsal-1 is a Xenopus homolog of spalt .