Probably acts as a transcriptional activator. Mediates neuronal differentiation. Required for the regulation of amacrine cell fate specification in the retina. Efficient DNA binding requires dimerization with another bHLH protein. Expressed in retinal interneurons amacrine cells (at protein level). Expressed in neurons of ventricular zone of the retina at postnatal day 1 (P1). Expressed transiently in amacrine and horizontal cells of the inner nuclear layer (INL) of the retina at P7 until P14. Weakly expressed in the neural tube around 8.5 dpc. By 9.5 dpc, expression is prominent in the ventral brain and spinal cord, and weak expression begins in the retina. At 10.5 dpc, highly expressed in the trigeminal and dorsal root ganglions, and the ventral midbrain and hindbrain. At 12.5 dpc, expressed in the mantle layer of the brain and spinal cord, trigeminal ganglion, Rathke's pouch, dorsal root ganglion and the ventricular zone of the neural retina. At 16.5 dpc, expression becomes restricted to the anterior region, persisting in the diencephalon and neural retina but decreasing in other regions. Serine or threonine phosphorylation within the basic region may regulate neurogenic activity.