Competence factors of retinal pigment epithelium cells for reprogramming in the neuronal direction during retinal regeneration in newts

Retinal pigment epithelium (RPE) cells that have the unique ability to reprogram retinal cells in vivo were analyzed in the adult newt. Our own data and that available in the literature on the peculiarities of the biology of these cells (from morphology to molecular profile, which can be associated with the capability of phenotype change) were summarized. It was established that the molecular traits of specialized and poorly differentiated cells are combined in RPE of the adult newt. It was registered that persistent (at a low level) proliferation and rapid change of specific cytoskeleton proteins can contribute to the success of RPE cell reprogramming in the neuronal direction. Each of the considered factors of competence for reprogramming can be found for animal RPE, whose cells are not able in vivo to change the phenotype to a neuronal one; however, their totality (supported by the epigenetic state permissive for conversion) is probably an internal property of only newt RPE.