Mutually Exclusive Odorant Receptor Regulation

描述（由申请人提供）：基因组是发育的主要工具，对生物体的遗传部分和程序进行编码。随着许多基因组的测序现在已经完成，寻求理解基因型和表型之间关系的下一个重大前沿是破译基因组信息是如何被调节的。这一前沿领域包含两个基本属性：基因组中“硬连接”的调控代码，指定基因表达的空间和时间模式，以及表观遗传影响，指定基因组响应的生物环境。本研究研究了一个复杂的气味受体（OR）基因调控系统，该系统可能揭示基因组的新遗传和表观遗传特性，从而为转录调控如何在全基因组范围内协调提供额外的见解。利用来源于前神经元祖细胞的细胞系，我们的实验将为嗅觉感觉神经元（OSNs）发育过程中互斥或表达的确定性和随机性提供见解。具体而言，我们将表征OSN祖细胞中受限的OR表达潜力，确定单一OR选择是否利用迭代调控机制，阐明OR共同调控的表观遗传学贡献，并研究OR RNA核定位的生物学意义。总的来说，这些研究将有助于我们了解基因组的结构组织和“组蛋白密码”，因为它与基因共调控和细胞分化有关。OSN细胞培养系统的开发和表征应该对神经科学界具有深远的效用，特别是考虑到嗅觉神经元是哺乳动物中唯一已知的能够在生物体的整个生命周期中再生的中枢神经元类型之一。表观遗传调控的研究对医学界也有着深远的影响，因为印迹相关疾病（如beckwithwithwiedemann综合征）、致癌转化和其他遗传疾病（如地中海贫血）都与正常染色质状态的扰动有关。总的来说，该项目将利用并进一步开发一个有前途的体外系统来研究OR表达和OSN的发展，提供一些关于OR表观基因组的第一批数据，并有助于我们了解基因组中固有的基因共调控程序。

DESCRIPTION (provided by applicant): The genome is the cardinal instrument of development that encodes the genetic parts and programs of an organism. With the sequencing of many genomes now complete, a next great frontier in the quest to understand the relationships between genotype and phenotype is to decipher how genome information is regulated. This frontier encompasses two essential attributes: regulatory code "hardwired" in genomes that specify spatial and temporal patterns of gene expression, and epigenetic influences that specify biological context to which a genome responds. This proposal investigates a complex odorant receptor (OR) gene regulatory system that is likely to reveal both novel genetic and epigenetic properties of the genome, and thus provide additional insights into how transcriptional regulation is coordinated genome-wide. Using cell lines derived from pre-neuronal progenitors, our experiments will provide insights into the deterministic and stochastic properties underlying mutually exclusive OR expression during the development of olfactory sensory neurons (OSNs). Specifically, we will characterize restricted OR expression potential in OSN progenitors, determine whether singular OR selection utilizes iterative regulatory mechanisms, elucidate epigenetic contributions to OR co-regulation, and investigate the biological significance of OR RNA nuclear localization. Broadly, these studies will contribute to our knowledge about the structural organization of genomes and the "histone code" as it pertains to gene co- regulation and cell differentiation. The development and characterization of an OSN cell culture system should have far-reaching utility to the neuroscience community, especially considering that olfactory neurons are one of the only known central neuron types in mammals that are capable of regeneration throughout the life of an organism. Research on epigenetic regulation also has far-reaching implications to the medical community, since imprinting-related diseases (e.g., Beckwith-Wiedemann syndrome), oncogenic transformation, and other genetic disorders (e.g., Thalassemia) are associated with perturbation of normal chromatin states. In total, this project will utilize and further develop a promising in vitro system for studying OR expression and OSN development, provide some of the first data on the OR epigenome, and contribute to our understanding of gene co-regulatory programs inherent in our genome.