LENS FIBER TRANSDIFFERENTIATION IN CULTURED LARVAL XENOPUS-LAEVIS OUTER CORNEA UNDER THE INFLUENCE OF NEURAL RETINA-CONDITIONED MEDIUM

The outer cornea of larval Xenopus laevis can reprogram cell different iation when cultured in medium conditioned by X. laevis neural retina (XRCM) or by Rana esculenta neural retina (RRCM). Under these experime ntal conditions corneal cells showed the same series of cytological ch anges of fibre cell differentiation observed during ontogenesis and is vivo lens regeneration: enlargement of nuclei and nucleoli, increase of ribosomal population (cytoplasm basophilia), cell elongation, gradu al loss of basophilic properties and acquisition of acidophilic proper ties for crystallin synthesis and accumulation. These events were comp letely dependent on XRCM or RRCM, suggesting that the neural retina se cretes a factor(s) which initiates and sustains lens fibre transdiffer entiation of the corneal epithelial cells. This culture system appears to be a suitable one for investigating the control of lens fibre tran sdifferentiation in vitro.