Department of Cell and Developmental Biology, University College, London, UK.
Dev Neurobiol. 2012 Mar;72(3):328-45. doi: 10.1002/dneu.20917.
Fish and amphibia are capable of lifelong growth and regeneration. The two core components of their visual system, the retina and tectum both maintain small populations of stem cells that contribute new neurons and glia to these tissues as they grow. As the animals age, the initial retinal projections onto the tectum are continuously remodeled to maintain retinotopy. These properties raise several biological challenges related to the control of proliferation and differentiation of retinal and tectal stem cells. For instance, how do stem and progenitor cells integrate intrinsic and extrinsic cues to produce the appropriate type and number of cells needed by the growing tissue. Does retinal growth or neuronal activity influence tectal growth? What are the cellular and molecular mechanisms that enable retinal axons to shift their tectal connections as these two tissues grow in incongruent patterns? While we cannot yet provide answers to these questions, this review attempts to supply background and context, laying the ground work for new investigations.
鱼类和两栖动物能够终生生长和再生。它们视觉系统的两个核心组成部分，视网膜和顶盖，都维持着一小部分干细胞，这些干细胞在组织生长过程中为这些组织提供新的神经元和神经胶质细胞。随着动物年龄的增长，最初投射到顶盖的视网膜不断重塑，以维持视网膜拓扑结构。这些特性带来了一些与控制视网膜和顶盖干细胞的增殖和分化相关的生物学挑战。例如，干细胞和祖细胞如何整合内在和外在的线索，产生生长组织所需的适当类型和数量的细胞。视网膜的生长或神经元的活动是否会影响顶盖的生长？在这两种组织以不协调的模式生长时，是什么细胞和分子机制使视网膜轴突改变它们在顶盖的连接？虽然我们还不能回答这些问题，但本综述试图提供背景和上下文，为新的研究奠定基础。
