Transcription factor essential for neural and some non-neural tissues development, such as retina and lung respectively. Binds to an 11-bp consensus sequence containing the invariant tetranucleotide 5'-ACGC-3'. During development of the central nervous system, is required to specify the amacrine and horizontal cell fates from multipotent retinal progenitors while suppressing the alternative photoreceptor cell fates through activating DLL4-NOTCH signaling. Also acts synergistically with ASCL1/MASH1 to activate DLL4-NOTCH signaling and drive commitment of p2 progenitors to the V2b interneuron fates during spinal cord neurogenesis. In development of non-neural tissues, plays an essential role in the specification of the atrioventricular canal and is indirectly required for patterning the distal airway during lung development. Mainly expressed in proliferator progenitor cells in brain and retina rather than differentiated cells. In contrast, is expressed only in postmitotic epithelial cells rather than in proliferative progenitors in the proximal airway. Expressed in both neural and non-neural tissues of the embryo. In the nervous system, its expression is detected only in a few selected central nervous system tissues including the midbrain, hindbrain, spinal cord and retina while absent from the peripheral nervous system. At about 9.5 dpc-10.5 dpc, commences its expression in the dorsal mesenphalon, ventral rhombencephalon and ventral spinal cord. In the spinal cord, is found in p2 progenitor cells but not in mature V2a and V2b cells, in other interneuron subtypes or in motoneurons. The expression in the brain and spinal cord becomes weak at 12.5 dpc and disappears by 13.5 dpc. In the central eye, expression starts in the central retina at 11.5 dpc, then gradually becomes abundant in the entire retinal outer neuroblastic layer by 13.5 dpc, but is absent from the inner neuroblastic layer. Starting from P1 and by P7, the expression in the retina gradually disappears from the center to the periphery. In airway system, expression turns on at 14.5 dpc in a small set of cells in the epithelia of the trachea and esophagus, then spreads to the epithelia of bronchi and bronchioles by 15.5 dpc, the expression persists until at least P8 (at protein level). Animals display early postnatal lethality, while survivors exhibit noticeable body size reduction starting at P8. At P8 and P20, retinas are reduced in thickness with the inner nuclear layer, inner plexiform layer and ganglion cell layer much thinner than in wild type and lack horizontal cells as well as amacrine cells. In lungs, mutants show dilated alveoli with thin walls.