Cloning & Functional Studies of Mouse Deafness Mutations

描述(申请人提供)：小鼠是研究人类听力障碍的极佳模型，因为两个物种的内耳解剖和功能相似。我们研究计划的总体目标是发现和表征新的小鼠耳聋突变，以(1)提高对正常听力过程和导致耳聋的病理基础的分子机制的理解，以及(2)为科学界提供新的小鼠模型。通过位置克隆鉴定了三个新的小鼠耳聋突变的基因，它们是匆忙-匆忙(Hscy)、环行(Rda)和吉特虫(Jitterbug)。这些基因以前都没有与听力或耳聋有关。这种更新应用的第一个目标是确定这三个基因的功能，因为它们与听觉系统的发育和维护有关。突变小鼠的内耳将通过电子显微镜检查超微结构异常，转录本和蛋白质的时空分布将通过原位杂交和免疫组织化学来确定。这项应用的第二个目的是识别第四种新的小鼠耳聋突变(超旋，hspn)背后的基因，这种突变导致内耳严重畸形。为了监测正常发育何时以及如何被破坏，将在多个时间点检查来自突变胚胎的内耳充满油漆的膜迷路。当hspn基因被确定后，它的表达模式将与可能作用于相同发育途径的其他基因的表达模式一起被评估。这项建议的第三个目标是继续我们的筛查计划，以识别新的小鼠耳聋突变，并确定它们的遗传、基因图谱位置和相关的内耳病理。听力障碍的遗传性已经被证实有28个新的突变，这些突变将被基因映射到5厘米或更低的分辨率。突变的内耳将被检查导致耳聋的解剖异常，这可能为基因功能提供线索。

DESCRIPTION (provided by applicant): The mouse is an excellent model for studying human hearing disorders because inner ear anatomy and function are similar in both species. The overall goal of our research program is to discover and characterize new mouse deafness mutations to (1) improve understanding of the molecular mechanisms that underlie the normal hearing process and pathologies that lead to deafness, and (2) provide new mouse models to the scientific community. The genes underlying three new mouse deafness mutations, hurry-scurry (hscy), roundabout (rda), and jitterbug (jbg), were identified by positional cloning. None of the genes have been previously associated with hearing or deafness. The first aim of this renewal application is to determine the functions of these three genes as they relate to the development and maintenance of the auditory system. Inner ears of mutant mice will be examined by electron microscopy for ultrastructural anomalies, and temporal and spatial distributions of transcripts and proteins will be determined by in situ hybridization and immunohistochemistry. The second aim of this application is to identify the gene underlying a fourth new mouse deafness mutation (hyperspin, hspn), which causes a gross malformation of the inner ear. To monitor when and how normal development is disrupted, paint-filled membranous labyrinths of inner ears from mutant embryos will be examined at multiple time points. When the hspn gene is identified, its expression pattern will be assessed along with those of other genes that may act in the same developmental pathway. The third aim of this proposal is to continue our screening program to identify new mouse deafness mutations and determine their inheritance, genetic map locations, and associated inner ear pathologies. Heritability of hearing impairment already has been proven for 28 new mutations, and these will be genetically mapped to a resolution of 5 cM or less. Mutant inner ears will be examined for anatomical abnormalities that lead to deafness and that may provide clues to gene function.