A mouse gene of the paired-related homeobox class expressed in the caudal somite compartment and in the developing vertebral column, kidney and nervous system.

 During vertebrate embryonic development, pairs of metameric units, the somites, bud off at the cranial end of the paraxial mesoderm. The somites soon obtain cranio-caudal and dorso-ventral polarity. Establishment of dorso-ventral and medio-lateral polarity depends on multiple signals from the notochord, neural tube surface ectoderm and lateral mesoderm.