Forkhead transcription factors are essential for diverse processes in early embryonic development and organogenesis. Foxd1 plays a dual role in the establishment of the binocular visual pathways: specification of the ventrotemporal (VT) retina, and patterning of the developing ventral diencephalon where the optic chiasm forms. Foxd1 is also required during kidney development and its inactivation results in failure of nephron progenitor cell differentiation. This lentivirus expresses human Foxd1 under the control of the Tet promoter.