Acts as a transcriptional activator that mediates transcriptional activation by binding to E box-containing promoter (5'-CANNTG-3') (PubMed:9310321, PubMed:9740021). Acts as a differentiation factor during neurogenesis (PubMed:9310321). Induces photoreceptor cell overproduction in vivo and de novo generation in vitro (PubMed:9740021). May play a role in photoreceptor cell production (PubMed:9740021). Efficient DNA binding requires dimerization with another bHLH protein. In the spinal cord it is found in neurons that are migrating or have reached their final position. Expressed in cells located at the outer portion of the developing retinal neuroepithelium, the location where prospective photoreceptors reside.