MOLECULAR BIOLOGY OF OLFACTORY RECEPTOR GENES

了解大脑的发育和功能需要 阐明了产生一种极大的 具有唯一身份的神经元的数量。 此外， 不同的神经元最终必须以特定的方式相互连接， 模式. 嗅觉系统提供了一个很好的模型系统， 因为1,000个嗅觉受体基因 作为功能不同的神经元子集的分子标记。 我们的初步研究表明，控制的层次结构对 嗅觉受体基因家族，例如给定的嗅觉神经元 只表达一千种可能基因中的一种 一个机制涉及 在调节嗅觉受体基因表达的等位基因失活 (only表达两个等位基因之一）。 根据这些研究， 这一建议的目的是阐明嗅觉受体的机制 基因调控和等位基因失活： 1. 为了确定DNA重排是否在选择哪种基因中起作用， 嗅觉受体表达。 2. 确定嗅觉调控中的顺式作用DNA元件 受体基因 3. 为了进一步表征等位基因失活并鉴定其 潜在的分子机制。 重排的潜在作用将在分子研究中得到解决 表达给定受体的纯化嗅觉神经元和细胞系 来源于嗅觉神经上皮。 一旦细胞选择了 一个给定的受体被分离出来，基因组DNA将被分析，以寻找 DNA重排。 与重新安排的问题无关，我们希望 了解控制的要素。 我们将使用酵母人工 染色体（YAC）来绘制编码嗅觉受体的基因座。 独联体 参与受体基因选择的作用DNA元件将在 转基因小鼠实验。 表征等位基因的实验 失活将涉及转录和DNA复制的分析， 细胞系和转基因小鼠。 这些研究将阐明基因调控导致 大脑中神经元多样性的显著产生， 对理解大脑功能紊乱有价值。 此外，委员会认为， 哺乳动物的嗅觉神经元在生物体的整个生命过程中再生。 因此，了解这些神经元所使用的基因表达机制， 对理解神经发育障碍有着特别的意义。

Understanding the development and function of the brain requires the elucidation of mechanisms underlying the generation of an extremely large number of neurons with unique identities. Moreover, the multitude of distinct neurons ultimately must connect to each other in specific patterns. The olfactory system provides an excellent model system for investigating these questions because the 1,000 olfactory receptor genes serve as molecular markers for functionally distinct subsets of neurons. Our preliminary studies indicate that a hierarchy of controls operates on the family of olfactory receptor genes, such that a given olfactory neuron expresses only one of the thousand possible genes. One mechanism involved in regulating olfactory receptor gene expression is allelic inactivation (only one of two alleles is expressed). Based on these studies, the aims of this proposal are to elucidate mechanisms underlying olfactory receptor gene regulation and allelic inactivation: 1. To determine if DNA rearrangement plays a role in the choice of which olfactory receptor is expressed. 2. To define the cis-acting DNA elements involved in regulating olfactory receptor genes. 3. To further characterize allelic inactivation and to identify its underlying molecular mechanisms. The potential role of rearrangement will be addressed in molecular studies of purified olfactory neurons expressing a given receptor and in cell lines derived from the olfactory neuroepithelium. Once cells which have chosen a given receptor are isolated, the genomic DNA will be analyzed to look for DNA rearrangement. Independent of the question of rearrangement, we wish to understand elements of control. We will use yeast artificial chromosomes (YACs) to map the loci encoding olfactory receptors. Cis acting DNA elements involved in receptor gene choice will be defined in transgenic mouse experiments. Experiments to characterize allelic inactivation will involve analyses of transcription and DNA replication in cell lines and transgenic mice. These studies will elucidate mechanisms through which gene regulation leads to the remarkable generation of neuronal diversity in the brain, and will be of value in understanding disorders of brain function. Moreover, mammalian olfactory neurons regenerate throughout the life of the organism. Thus, understanding the gene expression mechanisms used by these neurons is of particular relevance to understanding neurodevelopmental disorders.