Cannata Stefano M, Arresta Emiliano, Bernardini Sergio, Gargioli Cesare, Filoni Sergio
Department of Biology, Tor Vergata University, Rome, Italy.
J Exp Zool A Comp Exp Biol. 2003 Oct 1;299(2):161-71. doi: 10.1002/jez.a.10275.
After lentectomy through the pupillary hole, the outer cornea of larval Xenopus laevis can undergo transdifferentiation to regenerate a new lens. This process is elicited by inductive factor(s) produced by the neural retina and accumulated into the vitreous chamber. During embryogenesis, the outer cornea develops from the outer layer of the presumptive lens ectoderm (PLE) under the influence of the eye cup and the lens. In this study, we investigated whether the capacity of the outer cornea to regenerate a lens is the result of early inductive signals causing lens-forming bias and lens specification of the PLE, or late inductive signals causing cornea formation or both signals. Fragments of larval epidermis or cornea developed from ectoderm that had undergone only one kind of inductive signals, or both kinds of signals, or none of them, were implanted into the vitreous chamber of host larvae. The regeneration potential and the lens-forming transformations of the implants were tested using an antisense probe for pax6 as an earlier marker of lens formation and a monoclonal antibody anti-lens as a definitive indicator of lens cell differentiation. Results demonstrated that the capacity of the larval outer cornea to regenerate a lens is the result of both early and late inductive signals and that either early inductive signals alone or late inductive signals alone can elicit this capacity.
通过瞳孔孔进行晶状体切除术后，非洲爪蟾幼体的角膜外层可发生转分化以再生出新的晶状体。这一过程由神经视网膜产生并积聚在玻璃体腔中的诱导因子引发。在胚胎发育过程中，角膜外层在眼杯和晶状体的影响下由假定晶状体外胚层（PLE）的外层发育而来。在本研究中，我们调查了角膜外层再生晶状体的能力是早期诱导信号导致晶状体形成偏向和PLE晶状体特化的结果，还是晚期诱导信号导致角膜形成的结果，抑或是两种信号共同作用的结果。将仅经历过一种诱导信号、或两种诱导信号、或未经历任何诱导信号的外胚层发育而来的幼体表皮或角膜碎片植入宿主幼体的玻璃体腔中。使用针对pax6的反义探针作为晶状体形成的早期标志物，以及抗晶状体单克隆抗体作为晶状体细胞分化的确定性指标，来测试植入物的再生潜力和晶状体形成转化。结果表明，幼体角膜外层再生晶状体的能力是早期和晚期诱导信号共同作用的结果，并且单独的早期诱导信号或单独的晚期诱导信号都可以引发这种能力。
