Retinal progenitor cells (RPCs) retain the ability to generate different retinal cell types. RPCs appear to be retained in a progenitor state by the action of Notch-Delta signaling and downstream effectors of Notch, like the bHLH transcription factor Hes1. The most uncommitted RPCs (retinal stem cells) in the ciliary margin of the Xenopus retina were shown to coexpress the transcription factors Pax6, RX1, and Six3 prior to the activation of neurogenic genes (Notch, Delta, bHLH) and the subsequent steps toward retinal neurogenesis. Pax6 is required for the multipotent state of retinal progenitor C. Upon Pax 6 inactivation, the potential of RPCs becomes entirely restricted to only one of the cell fates normally available to RPCs resulting in the exclusive generation of amacrine interneurons. Pax6 has been found to directly control the transcriptional activation of retinogenic bHLH factors that bias subsets of RPCs towards different retinal cell fates, thereby mediating the full retinogen