RAX (Retina And Anterior Neural Fold Homeobox) is a homeobox-containing transcription factor that functions in eye development. RAX is required for retinal cell fate determination and also regulates stem cell proliferation. Mutations in this gene have been reported in patients with defects in ocular development, including microphthalmia, anophthalmia, and coloboma. RAX lentivirus (TET-inducible, Puro) expresses human RAX under the control of the Tet responsive promoter, with puromycin as a selection marker.