Probable transcription factor. Expressed in uncleaved zygotes with increasing intensity until the 8-cell stage. Confined to aboral region during 16-cell and 32-cell stage, afterwards found in ectodermal derivatives, in particular surrounding the blastopore and along the tentacular axis. Not expressed in the apical organ nor along the esophageal axis in mesodermal and endodermal derivatives. Expression subsides after hatching.