DEVELOPMENT STUDIES OF THE INNER EAR

听觉是人类交流能力的基础，而且 在儿童习得语言的过程中，这一点尤为重要。这个 内耳的感觉感受器细胞起着关键作用：它们的缺失 由于先天缺陷(先天性耳聋)，或在以后的生活中丧失， 会导致完全耳聋。抗击先天性耳聋和 由此造成的人类交流的缺陷，有必要了解 内耳的正常发育。随着耳朵的发育，细胞 组成耳朵的人必须经历一系列关键的决定 细胞类型(S)变成(即命运决定)，以及什么空间 它们必须与相邻单元格进行安排才能生成 适当的三维结构(即图案形成)。这个 这个项目的具体目标是(1)描述细胞命运的种类 脊椎动物内耳中单个祖细胞做出的决定 通过谱系分析和(2)测试一个候选分子的作用 在细胞命运决定和/或图案形成中。解决问题的方法 要实现这两个特定目标，主要需要使用逆转录病毒 载体作为一种高效的基因导入技术 进入鸡的发育中的内耳。针对特定目标1(世系 分析)，复制缺陷逆转录病毒载体将用于 传递编码碱性磷酸酶或β-磷酸酶的标记基因 半乳糖苷酶标记单个祖细胞，作为标记它们和 它们所有的后代。克隆分析将在以下阶段进行 区域和细胞类型的差异很明显。对于特定的 AIM 2(基因扰动)，复制能力强的逆转录病毒载体 编码各种形式的同源异型盒基因SOHO-1，将被使用 在内耳祖细胞中错误表达这种蛋白质。SOHO-1是 建议在细胞命运决定中扮演一个角色，涉及到 基于对其mRNA的初步描述而成为感觉器官 表达模式。这项研究的目的是进一步界定 SOHO-1的正常表达模式，并改变这种表达模式 在果穗形成的关键阶段。形成过程中的变化 SOHO-1错误表达导致的耳朵表明该基因 确实在建立正常的人体解剖结构方面起到了作用 耳朵。在此过程中建立的基因微扰方法 这项研究可以在未来用于测试许多其他候选基因 在耳朵发育中扮演一个角色。从基因中获得的表型 微扰实验可以模拟，并在某些情况下与 人类先天性内耳畸形。

The sense of hearing is fundamental to man's ability to communicate, and is particularly important in children as they acquire language. The sensory receptor cells of the inner ear play a pivotal role: their absence due to birth defects (congenital deafness), or their loss later in life, results in total deafness. To combat congenital deafness and the resulting deficits in human communication, it is necessary to understand the normal development of the inner ear. As the ear develops, the cells that comprise the ear must undergo a series of key decisions as to what cell type(s) to become (i.e., fate determination), and what spatial arrangements they must make with neighboring cells to generate the appropriate three-dimensional structure (i.e., pattern formation). The specific aims of this project are (1) to describe the kinds of cell fate decisions made by individual progenitor cells in the vertebrate inner ear through lineage analysis and (2) to test one candidate molecule for a role in cell fate determination and/or pattern formation. The methods for accomplishing these two specific aims primarily involve using retrovirus vectors as a highly efficient gene transfer technique to introduce genes into the developing inner ear of the chicken. For Specific Aim 1 (lineage analysis), replication-defective retrovirus vectors will be used to deliver a marker gene encoding either alkaline phosphatase or beta- galactosidase to individual progenitor cells as a way of labeling them and all of their progeny. Clonal analysis will be performed at a stage when regional and cell type distinctions are readily apparent. For Specific Aim 2 (gene perturbation), replication-competent retrovirus vectors that encode various forms of a homeobox-containing gene, SOHo-1, will be used to misexpress this protein in inner ear progenitor cells. SOHo-1 is proposed to play a role in the cell fate decision involving whether or not to become a sensory organ based on preliminary descriptions of its mRNA expression pattern. The purpose of this study is to further define the normal expression pattern of SOHo-1, and to alter this expression pattern during critical stages of ear formation. Alterations in the formation of the ear as a result of SOHo-1 misexpression would indicate that this gene does indeed play a functional role in establishing the normal anatomy of the ear. The gene perturbation methods established during the course of this study can be used in the future to test many other candidate genes for a role in ear development. The phenotypes obtained from gene perturbation experiments may mimic, and in some cases correlate with, human congenital malformations of the inner ear.