PROGRAMS OF GENE EXPRESSION IN OLFACTORY NEUROGENESIS

描述（由申请人提供）：神经系统中神经元多样性的产生是一个复杂的过程，涉及多种细胞谱系的特化和分化。连续的发育程序控制单个神经元类型的确定和增殖、细胞迁移、轴突延伸以及最终功能性突触连接的形成。这些步骤中的大多数是由特定的基因表达程序控制的，例如导致神经元前体产生的细胞命运决定。然而，成熟神经元从其祖细胞分化的遗传程序在很大程度上仍然未知，部分原因是在其天然环境中研究神经元干细胞的困难。 在脊椎动物的嗅觉系统中，初级感觉神经元通过神经祖细胞的增殖和分化在整个成年期不断再生。这一特征使得嗅觉系统特别适合于神经干细胞特性的研究。虽然这个谱系的某些阶段已经用一组有限的分子标记物鉴定，但定义和调节嗅觉神经发生的遗传程序在很大程度上仍然未知。这个生物学问题固有的巨大复杂性要求对基因表达有一个全局性的认识，以便充分了解这个发育系统中神经功能和发育的遗传网络。 在本申请中，我们提出了一套基于DNA微阵列的技术来识别-在全球范围内-对应于嗅觉神经元谱系的不同阶段的基因表达模式。我们建议（1）在胚胎发育和损伤诱导的再生过程中对嗅上皮的基因表达进行时间分析，以鉴定与该谱系的不同阶段相关的基因和基因表达程序，包括最早的多能祖细胞阶段;和（2）通过比较已知破坏嗅觉神经发生的突变体中的基因表达模式来完善该分析，并通过RNA原位杂交验证基于微阵列的预测。 我们的方法有望产生高度详细的信息，分子和途径负责嗅觉感觉神经元的起源，从他们的祖细胞。此外，一个更广泛的小组的分子标记物将产生不同阶段的嗅觉神经发生。在全基因组水平上阐明这些基因程序将为了解来自各种神经和非神经系统的祖细胞干细胞的特性提供有价值的见解。

DESCRIPTION (provided by applicant): The generation of neuronal diversity in the nervous system is a complex process involving the specification and differentiation of a multitude of cellular lineages. Successive developmental programs control the determination and proliferation of individual neuronal types, cell migration, axon extension, and ultimately the formation of functional synaptic connections. Most of these steps are controlled by specific gene expression programs, such as cell fate decisions that lead to the generation of neuronal precursors. The genetic programs underlying the differentiation of mature neurons from their progenitors remain largely unknown, however, in part because of the difficulty in studying neuronal stem cells in their native environments. In the vertebrate olfactory system, primary sensory neurons are continuously regenerated throughout adult life via the proliferation and differentiation of neural progenitor cells. This feature makes the olfactory system particularly amenable for studies on the properties of neuronal stem cells. While some stages of this lineage have been identified with a limited set of molecular markers, the genetic programs that both define and regulate olfactory neurogenesis remain largely unknown. The enormous complexity inherent in this biological problem demands a global view of gene expression in order to fully understand the genetic networks underlying neural function and development in this developmental system. In this application we propose a suite of DNA microarray-based techniques to identify - on a global scale - patterns of gene expression corresponding to distinct stages of the olfactory neuron lineage. We propose (1) to perform temporal profiling of gene expression in olfactory epithelium during embryonic development and lesion-induced regeneration to identify the genes and gene expression programs associated with distinct stages of this lineage, including the earliest multipotent progenitor stage; and (2) to refine this analysis by comparing gene expression patterns in mutants known to disrupt olfactory neurogenesis, and to validate the microarray-based predictions by RNA in situ hybridizations. Our approach is expected to yield highly detailed information about the molecules and pathways responsible for the genesis of olfactory sensory neurons from their progenitor cells. In addition, a broader panel of molecular markers will be generated for distinct stages of olfactory neurogenesis. The elucidation of these, qenetic programs at the genome-wide level will provide valuable insights into the properties of progenitor stem cells from a variety of neural and non-neural systems.