Model representing the process of chick retinal pigmented epithelium transdifferentiation. Phase I includes dedifferentiation. During this phase, there is no proliferation. During step 1, injury signals are produced in response to retinectomy; pluripotency-induced factors Sox2, c-Myc and Klf4 that are also present in retina progenitors are up-regulated as well as eye field transcriptional factors (EFTFs), along with a down-regulation of RPE specific markers. During step 2, after the addition of exogenous FGF2, Lin-28, is up-regulated; however, during this stage there is no cell proliferation. In Phase II, in the presence of FGF2, proliferation is initiated. Lastly, on Phase III, differentiation of retinal cells takes place.