Abstract：
The process of morphogenesis carefully crafts cells into complex organ structures which allows them to perform their unique functions. During brain development, the neuroepithelial tissue must go through apical and basal folding which is mediated through the instruction of both intrinsic and extrinsic factors. While much is known about apical folding, the mechanisms that regulate basal folding are less understood. Using the highly conserved zebrafish midbrain-hindbrain boundary (MHB) as an epithelial tissue model, we have identified the basement membrane protein laminin-111 as a key extrinsic factor in basal tissue folding. Laminin-111 is a highly conserved, heterotrimeric protein that lines the basal surface of the neuroepithelium. Laminin-111 is comprised of one alpha, one beta, and one gamma chain encoded by the genes lama1, lamb1, and lamc1, respectively. Human mutations in individual laminin-111 genes result in disparate disease phenotypes; therefore, we hypothesized that each laminin gene would have a distinctive role in tissue morphogenesis. Using zebrafish mutants for laminin-111 genes, we found that each laminin chain has a unique impact on basal folding. We found that lamc1 is the most critical gene for MHB morphogenesis, followed by lama1, and finally lamb1a. This hierarchy was discovered via three-dimensional single cell shape analysis, localization of myosin regulatory light chain (MRLC), and with analysis of MHB tissue folding later in development. These findings are essential for development of novel techniques in tissue engineering and to elucidate differences in human diseases due to specific chain mutations.
摘要：
形态发生的过程仔细地将细胞加工成复杂的器官结构，使它们能够执行其独特的功能。在大脑发育过程中,神经上皮组织必须经历顶端和基底折叠，这是由内在和外在因素的指导介导的。虽然人们对根尖折叠了解很多，对调节基底折叠的机制了解较少。使用高度保守的斑马鱼中脑-后脑边界（MHB）作为上皮组织模型，我们已经确定基底膜蛋白层粘连蛋白-111是基底组织折叠的关键外在因素。层粘连蛋白-111是一种高度保守的，排列在神经上皮基底表面的异源三聚体蛋白。层粘连蛋白-111由一个alpha组成,一个测试版,和一条分别由基因lama1，lamb1和lamc1编码的γ链。个体层粘连蛋白-111基因中的人类突变导致不同的疾病表型；因此，我们假设每个层粘连蛋白基因在组织形态发生中具有独特的作用。使用斑马鱼突变体进行层粘连蛋白-111基因，我们发现每个层粘连蛋白链对基底折叠有独特的影响。我们发现lamc1是MHB形态发生最关键的基因，其次是lama1，最后是lamb1a。这种层次结构是通过三维单细胞形状分析发现的，肌球蛋白调节轻链（MRLC）的定位，并在发育后期分析MHB组织折叠。这些发现对于组织工程新技术的发展以及阐明由于特定链突变而导致的人类疾病的差异至关重要。
