Testing the genetic conservation of tooth and hair replacement

项目摘要 对组织再生的遗传机制的完整理解是进一步研究的必要条件。 再生医学和诊断医学的进展。虽然基因调控网络的某些部分 基本的器官和组织再生是了解的，我们缺乏关于这些数据是否/如何的基本知识， 也适用于其他器官和组织类型，不同参与细胞的参与水平 层次。这项工作的总体目标是解剖斑马鱼和棘鱼的牙齿再生， 非常适合这种调查。而大多数哺乳动物的牙齿只更换一次或零次 在它们的生命中，大多数其他脊椎动物物种（鱼类，两栖动物，爬行动物等）都会再生它们的 牙齿不断尽管如此，牙齿干细胞或干细胞样细胞的基因级联反应 它们的祖先在很大程度上仍是个谜。鱼类具有强大的遗传优势，包括大量的 快速发育的后代，体外受精，高效的转基因和基因组编辑 方法.米勒实验室对棘鱼进行了无偏见的研究，棘鱼会不断更换牙齿。 确定骨形态发生蛋白6（Bmp 6）衰减为与牙齿相关的遗传事件 再生该机制模拟哺乳动物毛发再生，其中BMP衰减对于毛发再生至关重要。 从成熟毛发向替换毛发转变。此外，RNA-seq已经鉴定出强阳性和 棘鱼Bmp 6 mRNA水平与可能参与 牙齿再生，其中许多也涉及毛发再生，如Lgr 6和Wnt途径 基因.因此，在头发中，BMP衰减似乎是替换牙齿开始的关键事件。 这些数据表明，这些再生程序使用一个共享的基因调控网络，早于我们的研究。 最后的水生亲属和他们不断更换的牙齿。利用这些丰富的初步数据， Bmps的上游和下游，以进一步阐明负责 牙齿再生和测试牙齿和头发再生从一个共同的遗传程序的假设。到 为此，我将确定牙齿再生过程中与假定的干细胞相关的基因表达模式 小生境（特定目标1），测试保守的遗传机制是否调节和抑制牙齿中的Bmp 6信号， 以及这些是否与生态位维持有关（特异性目标2），并分析Bmp的作用 在小生境中激活Wnt信号传导的信号传导活性（特异性目标3）。将这些数据与其他 器官系统，即头发，将填补我们关于组织再生知识的关键空白， 未来尝试在体外和最终在体内再生人类牙齿和其他组织的方法。

Project Summary A complete understanding of the genetic machinery underlying tissue regeneration is desirable for further advances in regenerative and diagnostic medicine. While some parts of the gene regulatory networks underlying organ and tissue regeneration are understood, we lack basic knowledge regarding if/how such data are applicable to other organ and tissue types, and the levels of involvement from the different participating cell layers. The overall goal of the proposed work is to dissect tooth regeneration in zebrafish and stickleback fish, which are well suited to such inquiries. While most mammalian teeth are replaced only one or zero times during their lives, the majority of other vertebrate species (fishes, amphibians, reptiles, etc) regenerate their teeth constantly. Despite this fact, the genetic cascades underlying dental stem cells or stem-cell like progenitors remain largely mysterious. Fish offer powerful genetic advantages including large numbers of rapidly developing offspring, external fertilization, and highly efficient transgenesis and genome editing methods. Using an unbiased approach in sticklebacks, which constantly replace their teeth, the Miller lab identified Bone morphogenetic protein 6 (Bmp6) attenuation as a genetic event correlated with tooth regeneration. This mechanism mimics mammalian hair regeneration, wherein BMP attenuation is crucial for a shift from mature hair to replacement hair initiation. Furthermore, RNA-seq has identified strong positive and negative correlations between stickleback Bmp6 mRNA levels and the expression of genes likely involved in tooth regeneration, many of which are also implicated in hair regeneration, such as Lgr6 and Wnt pathway genes. Thus, as in hair, Bmp attenuation appears to be a key event in the initiation of replacement teeth. These data suggest that these regeneration programs use a shared gene regulatory network that predates our last aquatic relatives and their continuously replaced teeth. Using this wealth of preliminary data, I will look both upstream and downstream of Bmps in order to further elucidate the genetic pathways responsible for tooth regeneration and to test the hypothesis that teeth and hair regenerate from a shared genetic program. To this end, I will identify gene expression patterns during tooth regeneration associated with putative stem cell niches (Specific Aim 1), test if conserved genetic mechanisms regulate and transduce Bmp6 signals in teeth, and whether these are associated with niche maintenance (Specific Aim 2), and assay the role of Bmp signaling activity in the activation of Wnt signaling in the niche (Specific Aim 3). Comparing these data to other organ systems, namely hair, will fill critical gaps in our knowledge regarding tissue regeneration, paving the way for future attempts to regenerate human teeth and other tissues in vitro and ultimately in vivo.