Reptilian tooth and jaw development

爬行动物牙齿和下颌的发育

• 批准号: 326908-2011
• 负责人: Richman, Joy
• 金额: $ 4.56万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=481495
• 关键词: Reptilian; tooth; jaw; development

This grant will study the formation of the teeth and jaws of reptiles. The first aim we will study the genes involved in replacement of teeth. Rodents are the most common model to study tooth development but their weakness is that they only have one set of teeth. To overcome this problem the proposed research use snakes and lizards that replace their teeth throughout life. In previous studies, we identified a network of signaling factors that control tooth initiation in pythons and geckos. Now we will add in two more signaling pathways and will expand our studies to later stages of tooth replacement. The importance of studying this question is that we will understand why some orders of animals have lost the ability to replace their teeth, while others form multiple sets. We will also address the contribution of 'stem cells' to tooth replacement. Our previous work suggested that putative stem cells are present in gecko teeth. Here we will activate these putative stem cells and follow their contributions to replacement teeth. The second aim of the grant will focus on skull development. Our preliminary studies have shown that the palates of snakes, lizards and birds are quite similar to mammals since they all pass through a similar intermediate stage. In contrast, turtles lack the transient structures called palatal shelves, yet the palatine bones still form and meet in the midline. The proposed experiments here will discover how the turtle palate is formed by taking a different developmental path. Finally we will be addressing the embryonic origins of the unique and ancient turtle skull shape. We will identify a group of genes that are different in the turtle versus the chicken and then we will test whether they are sufficient to make the bird skull more like that of the turtle. In summary, our application of current developmental biology techniques to reptiles will provide a wealth of new insights into evolution including why humans and other mammals are limited to 2 sets of teeth and whether or not turtles are the most primitive reptile order.

这笔拨款将用于研究爬行动物牙齿和下颚的形成。第一个目标是研究与牙齿替换有关的基因。啮齿类动物是研究牙齿发育最常见的模型，但它们的缺点是只有一套牙齿。为了克服这个问题，研究人员建议使用蛇和蜥蜴来替换它们的牙齿。在之前的研究中，我们发现了一个控制蟒蛇和壁虎牙齿形成的信号因子网络。现在我们将增加另外两个信号通路，并将我们的研究扩展到牙齿替换的后期阶段。研究这个问题的重要性在于，我们将理解为什么一些目的动物失去了更换牙齿的能力，而另一些目的动物却形成了多组牙齿。我们还将讨论“干细胞”对牙齿替代的贡献。我们以前的工作表明，壁虎牙齿中存在假定的干细胞。在这里，我们将激活这些假定的干细胞，并跟踪它们对替换牙齿的贡献。该基金的第二个目标将集中于颅骨发育。我们的初步研究表明，蛇、蜥蜴和鸟类的味觉与哺乳动物非常相似，因为它们都经历了类似的中间阶段。相比之下，海龟缺乏被称为腭架的短暂结构，但腭骨仍然形成并在中线相遇。这里提出的实验将通过采取不同的发育路径来发现海龟的腭是如何形成的。最后，我们将讨论独特而古老的海龟头骨形状的胚胎起源。我们将确定海龟和鸡的一组不同的基因，然后我们将测试它们是否足以使鸟类的头骨更像海龟的头骨。总之，我们将当前的发育生物学技术应用于爬行动物，将为进化提供丰富的新见解，包括为什么人类和其他哺乳动物仅限于2套牙齿，以及海龟是否是最原始的爬行动物。