Transformation of retinal glia cells into lens phenotype: expression of MP26, a lens plasma membrane antigen.

We describe experiments in which dissociated cells from differentiated, post-mitotic neural retina of late chicken embryos (13 and 16 days) rapidly and consistently transform (transdifferentiate) in vitro into lens-like phenotype and form spherical lentoids. Using immunohistochemical and other tests, we have established that the lentoids arise from the progeny of definitive retinal glia cells (Müller cells). An early event in their transformation is the appearance in the cell surface of MP26, a plasma membrane protein characteristic of lens but not found in the retina. The results support the hypothesis that the phenotype of definitive glia cells in the retina is stabilized by contact-mediated interactions with neurons; disruption of cell contacts and cell separation alter surface properties of the glia cells, decontrol their phenotype, and predispose them to phenotype transformation.