Appears to regulate regional development of specific tissues. Can rescue axis polarity in UV-radiated Xenopus embryos. In early embryo development, expression confined to two regions; a horseshoe-like pattern across the dorsal side which is destined to form the brain hemispheres and a second domain which invaginates inside the stomodeum and which, is fated to form the foregut, ring gland and stomatogastric nervous system (SNS). Belongs to the paired homeobox family. Bicoid subfamily. Extended N-terminus. Extended N-terminus.