Binds to the 37-bp core of the locus control region (LCR) of the red/green visual pigment gene cluster. May regulate the activity of the LCR and the cone opsin genes at earlier stages of development (By similarity). Dispensable in early retinal development (By similarity). Restricted to bipolar cells of the retina and spinal cord. At stage 12, expressed throughout the invaginating optic vesicles and a subset of cells in the ventral spinal cord, presumably interneuron precursors. At stage 14, when the optic cup forms, expression is restricted to a subset of retinoblasts. At stage 15, expression along the ventral spinal and hindbrain intensifies and persists beyond stage 20. Belongs to the paired homeobox family.