May participate in maintenance of mesenchymal cell lineages derived from both mesoderm and the neural crest and in patterning of the limbs and the face. Interacts with MAF and MAFB. Expressed predominantly in the mesodermal cells of the limb bud, visceral arches and craniofacial process, and at lower levels, in cranial mesenchyme, upper and lower eyelids, somites and cartilage of vertebra. Also found in the heart, especially the developing semilunar and atrioventricular valves and in the brain, in a distinct region of the ventral part of the hypothalamus as well as in a broader region of the telencephalon. At stage 10, expressed in the neural tube throughout the mesoderm. By early stage 13, expression becomes restricted to the lateral mesoderm in the trunk region and in the cranial region, to the dermomyotome, to the somatic mseoderm-derived pericardium and to a group of cells located ventral to the dermomyotome. Expression continues at high levels in the dermatome. In later stages, high expression found in the limb bud mesenchyme pharyngeal arches, the maxillary arches and the frontonasal mass and to a lesser extent, in the aorta, cardiac valve mesenchyme, the pericardial wall and the ventral foregut wall. Belongs to the paired homeobox family.