Transcriptional regulator that has an essential role in the organogenesis of lungs, pelvis, and hindlimbs. First expressed at day 7.5, exclusively in the allantois where expression continues through day 8.5. At day 9.5, expression is found in the genital papilla, body wall and limb buds (higher levels in hindlimb). At day 12.5, expressed in the mesenchyme of the mandibular arch, of the lung and of that surrounding the trachea. Also found in the sinus venosus/common atrium of the developing heart.