The role of Tex15 in shaping stochastic olfactory receptor gene choice.

项目摘要/摘要 令人难以置信的特异性，我们可以辨别出各种各样的气味从如何嗅觉 感觉神经元表达嗅觉受体(OR)基因。这些OR基因编码结合蛋白 化学气味。每个OSN只随机转录一个OR基因的等位基因。OSN可以选择 表达大约1400个OR基因或2800个等位基因中的任何一个。没有一对一的关系 在气味和OR之间作为OR的组合涉及到一种气味的检测。因此， ORs表达的多样性对主要嗅觉上皮(MOE)检测大量 各种气味。 OR基因的选择发生在OSN祖细胞成熟为OSN的过程中。最近的研究揭示了 在此期间，局部染色质显著重塑和多个OR基因的共同表达，但 控制这些过程的分子机制及其与单个OR等位基因表达的关系 在一个成熟的OSN中仍然是未知的。 我们发现睾丸表达15(德克萨斯15)，这是一种只在睾丸中研究过的蛋白质，在那里它调节 转座子的甲基化和沉默，是随机或基因选择的关键。我们发现，当德克萨斯15号 基因敲除后，表达的OR基因与少数OR基因的多样性显著降低 主宰随机选择。值得注意的是，Tex15仅在OSN前体细胞中瞬时表达 或共同表达的时期。我们的中心假设是，Tx15是表观遗传控制的随机或 基因选择，通过调节DNA甲基化或OR基因染色质结构的其他方面。目标1将 确定OSN中多个OR基因的瞬时共表达是否需要Tex15 祖先。在目标2中，我们将确定Tex15蛋白是否与OR基因结合。最后在《目标3》中，我们的 对Tex15缺失小鼠的原代OSNs的实验将确定基因抑制是如何在 OSN前体--通过甲基化或抑制异染色质沉积。 总而言之，这些实验将阐明OSN如何随机选择一个 或者，以及德克萨斯15基因和蛋白质如何引导这一特定而多样化的选择。我们预计这个项目将 发现Tex15在教育部的新角色和/或意想不到的角色。这也将揭示关键分子 为我们的嗅觉如何发展奠定了基础，并可能为进一步理解 嗅觉紊乱的机制。拟议的奖学金将培训这位申请者几种创新的技术。 在生化、细胞、分子和计算神经科学方面。老牌师范生 导师制将确保适当的科学和专业培训，这是成为一名成功的 独立的感觉和计算神经生物学家。

PROJECT SUMMARY/ABSTRACT The incredible specificity with which we can discern a vast diversity of smells emerges from how olfactory sensory neurons (OSN) express olfactory receptor (OR) genes. These OR genes encode the proteins that bind chemical odorants. Each OSN stochastically transcribes only one allele of an OR gene. An OSN can choose to express any one of the approximately 1400 OR genes or 2800 alleles. There is no one to one relationship between an odorant and an OR as a combination of ORs are involved in the detection of one odorant. Thus, the diversity of ORs expressed is important to the main olfactory epithelium’s (MOE) ability to detect a vast range of smells. The choice of an OR gene occurs as OSN progenitors mature into an OSN. Recent work has revealed remarkable remodeling of the local chromatin and co-expression of multiple OR genes during this period, but the molecular mechanisms governing these processes and their connection to a singular OR allele expression in a mature OSN remain unknown. We show that testis expressed 15 (Tex15), a protein that has only been studied in the testes where it regulates methylation and silencing of transposons, is crucial for stochastic OR gene choice. We find that when Tex15 is knocked out there is a dramatic reduction in the diversity of expressed OR genes with a few OR genes dominating stochastic choice. Strikingly, Tex15 is only transiently expressed in OSN progenitors during a period of OR co-expression. Our central hypothesis is that Tex15 is epigenetically controlling stochastic OR gene choice, either by regulating DNA methylation or other aspects of OR gene chromatin structure. Aim 1 will determine whether Tex15 is required for transient co-expression of multiple OR genes in OSN progenitors. In aim 2, we will determine whether Tex15 protein binds to OR genes. Finally in aim 3, our experiments on primary OSNs from Tex15 null mice will determine how gene repression is mediated in OSN progenitors – through methylation or deposition of repressive heterochromatin. Together, these experiments will elucidate a novel aspect of how OSNs come to stochastically choose a single OR and how Tex15 gene and protein guides this specific yet diverse choice. We anticipate this project will uncover new and/or unexpected role for Tex15 in the MOE. This will also reveal the key molecular underpinnings for how our sense of smell develops and may provide important insight to further understand the mechanisms of smell disorder. The proposed fellowship will train this applicant in several innovative techniques in biochemical, cellular, molecular, and computational neuroscience. The established faculty-student mentorships will ensure proper scientific and professional training necessary to become a successful, independent sensory and computational neurobiologist.