Members of the Pax family of transcription factors contain a paired box DNA binding domain and may or may not contain a paired-type homeodomain and/or octapeptide region. Nine Pax genes have been identified in mammals and are divided into four subgroups based on the sequence elements present. Pax genes play a variety of roles during embryogenesis, regulating cell-lineage specification, proliferation, migration, and survival of diverse cell and tissue types. Several of the Pax genes are also expressed in cancers and serve as tumor markers.
Pax6 is a highly conserved transcription factor essential for the development of tissues including the eyes, central nervous system, and endocrine glands of vertebrates and invertebrates. Pax6 is a key regulator that is required for normal islet development.