Filoni Sergio
University of Rome, Dept. of Biology, Italy.
Semin Cell Dev Biol. 2009 Jul;20(5):528-34. doi: 10.1016/j.semcdb.2008.11.015. Epub 2008 Nov 27.
Anuran amphibians can regenerate the retina through differentiation of stem cells in the ciliary marginal zone and through transdifferentiation of the retinal pigmented epithelium. By contrast, the regeneration of the lens has been demonstrated only in larvae of species belonging to the Xenopus genus, where the lens regenerates through transdifferentiation of the outer cornea. Retinal pigmented epithelium to neural retina and outer cornea to lens transdifferentiation processes are triggered and sustained by signaling molecules belonging to the family of the fibroblast growth factor. Both during retina and lens regeneration there is a re-activation of many of the genes which are activated during development of the eye, even though the spatial and temporal pattern of gene expression is not a simple repetition of that found in development.
无尾两栖动物可通过睫状边缘区干细胞的分化以及视网膜色素上皮的转分化来再生视网膜。相比之下，晶状体再生仅在非洲爪蟾属物种的幼体中得到证实，在这些物种中，晶状体通过外角膜的转分化进行再生。视网膜色素上皮向神经视网膜以及外角膜向晶状体的转分化过程由成纤维细胞生长因子家族的信号分子触发并维持。在视网膜和晶状体再生过程中，许多在眼睛发育过程中被激活的基因都会重新激活，尽管基因表达的时空模式并非简单重复发育过程中的模式。
