Ganglion cell development: Early steps/fate

Retinal ganglion cells (RGCs) transmit integrated visual information to the brain. In the vertebrate retina, these neurons differentiate first, and project axons relatively long distances to form synapses in discrete areas of the brain. A transcription factor network orchestrates the development of RGCs, in part by integrating positive and negative regulatory inputs from signal transduction pathways. Two genes, atonal homolog 7 (Atoh7) and Pou domain class 4 factor 2 (Pou4f2), are critical integration points for this information. These transcription factors each regulate multiple downstream genes that participate in neuronal specification, differentiation, axon outgrowth/guidance, and neuronal survival. Despite remarkable progress in identifying the molecules critical for RGC development, much more work remains to decipher and assemble a complete genetic hierarchy.