Acts as a transcriptional regulator of muscle creatine kinase (MCK) and so has a role in the establishment of diverse mesodermal muscle types. The protein binds to an A/T-rich element in the muscle creatine enhancer. Expressed exclusively in mesodermally derived cell types. During embryogenesis, highest levels of expression are found in the mesenchyme and precartilage elements of the face and hind limbs. In the adult, expression is restricted to skeletal muscle, heart and uterus. Expressed during cardiogenesis. Belongs to the paired homeobox family.