Mexican tetra (Astyanax mexicanus) as a model to understand the development and regeneration of the epithelial appendages

洞穴动物是退化进化的经典例子；然而，它们也进化出具有建设性的特征，以弥补永远黑暗中的生活。小型淡水鱼墨西哥Tetra是一种新的动物模型，以两种形态存在：有眼的、有色的水面栖息型(表层鱼/SF)和无眼的无色的洞穴型(Cavefish/CF)。为了更好地适应地下环境，CF进化出了形态、感觉和行为特征。Cf具有增强的上皮结构，包括牙齿、味蕾(TBS)和神经肥大细胞(NMC)。NSERC DG计划的长期目标是以墨西哥河豚为动物模型，确定脊椎动物上皮性附肢发育和再生的潜在机制。在墨西哥的Tetra，我们发现不同的眼睛表型在牙齿数量、形态、图案和去除SF头部一侧的晶状体改变了颅面部区域的基因表达。根据这些发现，我推测CF在上皮性附件的发育和再生中具有高级的细胞和分子机制。我解决这一假说的短期目标是：1)了解眼球退变对颅面部上皮性附属物发育和再生的影响。我们将使用组织学和胚胎处理技术来确定与上皮性附件发育和再生相关的变化的遗传基础。此外，这些数据将突出Shh(Sonic Hedgehog)过度表达对该物种上皮性附属物发育的任何可能的梯度效应。2)探讨神经脊细胞(NCC)迁移对CF上皮性附件发育的影响。采用细胞标记和NCC移植技术，比较SF和CFNCC在不同发育阶段的迁移模式。这些数据将显示NCC迁移行为的改变及其对颅面发育的影响。3)探讨胚层起源在上皮性附件图案化中的适应性意义。利用细胞标记技术和基因表达分析，我们将比较外胚层来源的上皮性附件和内胚层来源的附件。这一数据将为该物种上皮性附属物发育的微观进化机制提供洞察力。意义：通过我的HQP，我们将促进对上皮性附件发育和再生机制的理解，同时为HQP提供发育和分子细胞生物学技术方面的宝贵技能。它们是组织工程、兽医和水产养殖应用中的生物学研究所必需的。总之，拟议的计划将增加我们对脊椎动物上皮性附属物基本发育机制的理解。

Cave dwelling animals are classic examples of regressive evolution; however, they also have evolved constructive features to compensate for life in perpetual darkness. The small fresh water fish, Mexican tetra (Astyanax mexicanus), is a novel animal model and exists as two morphological types: an eyed, pigmented surface-dwelling form (surface fish /SF) and an eyeless, unpigmented cave-dwelling form (cavefish /CF). The CF have evolved with morphological, sensory and behavioural traits for better adaptation to a subterranean environment. CF have enhanced epithelial structures, including teeth, taste buds (TBs) and neuromast cells (NMC). The long-term goal of this NSERC DG program is to identify the mechanisms underlying the development and regeneration of the epithelial appendages of vertebrates using Mexican tetra as an animal model. In Mexican tetra, we found different eye phenotypes have variation in tooth number, morphology, patterning and removal of the lens on one side of the head of SF altered the gene expression in the craniofacial region. Based on these findings, I hypothesize CF has advanced cellular and molecular mechanisms for the development and regeneration of epithelial appendages. My short-term objectives to address this hypothesis are: 1)To understand the effect of eye degeneration on the development and regeneration of epithelial appendages in the craniofacial region. We will use histological and embryo manipulation techniques to identify the genetic basis for changes associated with epithelial appendage development and regeneration. Further, this data will highlight any possible gradient effect of Shh (Sonic Hedgehog) overexpression on epithelial appendage development in this species. 2)To characterise the influence of neural crest cell (NCC) migration on CF epithelial appendage development. Cell labeling and NCC transplantation techniques will be used to compare the migratory pattern of the NCC of SF and CF at different developmental stages. This data will demonstrate the altered migratory behaviour of the NCC and its effect on craniofacial development. 3)To investigate the adaptive significance of germ layer origin in patterning the epithelial appendages. Using cell labeling techniques and gene expression analysis we will compare the ectodermal derived epithelial appendages with endodermal derived appendages. This data will provide insight to the microevolutionary mechanisms of epithelial appendage development of this species. Significance: With my HQP we will advance the understanding of the development and regenerative mechanisms of the epithelial appendages while giving HQP valuable skill set in developmental and molecular cell biology techniques. These are needed for the biological research in tissue engineering, veterinary and aquaculture applications. In summary, the proposed program will increase our understanding of the fundamental developmental mechanisms of epithelial appendages in vertebrates.