Paired box protein Pax-9, also known as PAX9, is a member of the paired box (PAX) family of transcription factors. Members of this gene family typically contain a paired box domain, an octapeptide, and a paired-type homeodomain. These genes play critical roles during fetal development and cancer growth. PAX9 is essential for the development of a variety of organs and skeletal elements. Recombinant human PAX9 protein, fused to His-tag at N-terminus, was expressed in E.coli.