Study of the deafness gene Grxcr1 and a paralog, Grxcr2

耳聋基因 Grxcr1 和旁系同源基因 Grxcr2 的研究

• 批准号: 7583889
• 负责人: David C Kohrman
• 金额: $ 29.13万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7583889
• 关键词: Actins; Adenoviruses; Amino Acids; Apical; Architecture; Biochemical; Biological; C-terminal; Caliber; Cell Line; Cell model; Cells; Cellular Morphology; Cultured Cells; Cysteine-Rich Domain; Cytoskeleton; Development; Dorsal; Ear; Enzymes; Exhibits; Fibroblasts; Functional disorder; Generations; Genes; Genetic; Hair Cells; In Vitro; Infection; Labyrinth; Link; Mediating; Metabolism; Microfilaments; Modeling; Molecular; Molecular Genetics; Mus; Mutant Strains Mice; Mutation; Oxidation-Reduction; Pathology; Pathway interactions; Physiological; Process; Proteins; Recombinants; Regulation; Relative (related person); Role; Sensorineural Hearing Loss; Sensory; Sensory Hair; Stereocilium; Structure; Surface; Tissues; Transfection; base; deafness; embryonic stem cell; glutaredoxin; homologous recombination; insight; mutant; novel; null mutation; paralogous gene; postnatal; selective expression

DESCRIPTION (provided by applicant): Recessive mutations at the mouse pirouette (pi) locus cause sensorineural deafness and vestibular dysfunction due to defective maturation of sensory hair cells in the inner ear. We have recently identified the genetic basis of these pathologies as null mutations in a novel gene, Grxcr1. Pathology in pirouette sensory cells suggests that this gene is required for increasing the diameter of stereocilia during early postnatal maturation of sensory cells, potentially through regulation of actin filament distribution in the stereocilia core. Grxcr1 is expressed in sensory cells of the inner ear and encodes a 290 amino acid protein containing a central domain with significant similarity to glutaredoxin proteins, and a C-terminal cysteine-rich domain. Transfection of Grxcr1 constructs into cultured cells indicates that it localizes to actin filament-rich structures at the dorsal/apical surface. In addition, the actin filament content in dorsal projections in transfected fibroblasts often appears more prominent on cells expressing GRXCR1, suggesting a local, direct role for the protein in the induction and/or stabilization of the actin cytoskeleton of these structures. Grxcr1-related genes are present in a wide range of metazoan species, including a related paralogous gene (Grxcr1) also expressed selectively in the mouse inner ear. Using molecular genetic and cell biological approaches, we propose to investigate the biochemical, cellular, and physiological roles of GRXCR1 and GRXCR2. We will determine the sub cellular localization of these proteins in inner ear tissues (Aim 1), identify domains required for activities of the proteins in vitro, in cultured cells and inner ear tissue explants, and examine the interdependence of these activities (Aim 2), identify additional proteins that may interact directly with GRXCR1 (Aim 3), and generate a targeted mutation of Grxcr2 to characterize a potential novel model of inner ear dysfunction (Aim 4). Through these aims, we will investigate potential links between stereocilia development, actin dynamics, and processes influenced by reduction/oxidation pathways, and thereby provide insight into the molecular control of sensory cell development and function.

描述（由申请人提供）：小鼠pirouette（PI）基因座的隐性突变导致感觉性耳聋和前庭功能障碍，这是由于内耳内耳中感觉毛细胞的成熟不良而导致的。我们最近将这些病理学的遗传基础确定为新基因GRXCR1中的无效突变。 Pirouette感觉细胞中的病理表明，在感觉细胞早期成熟期间，该基因增加了立体胶质的直径，这可能是通过调节立体核心核心中肌动蛋白丝分布的可能性。 GRXCR1在内耳的感觉细胞中表达，并编码一个290个氨基酸蛋白，该氨基酸蛋白包含与谷杆菌蛋白具有显着相似性的中心结构域和富含C-末端半胱氨酸的结构域。将GRXCR1构建的转染到培养的细胞中表明，它本地化为肌动蛋白细丝在背面/顶表面的结构。此外，转染的成纤维细胞中背型的肌动蛋白细丝含量通常在表达GRXCR1的细胞上显得更为突出，这表明蛋白质在诱导和/或稳定这些结构的肌肉骨骼中具有局部直接作用。与GRXCR1相关的基因存在于广泛的后生动物中，包括相关的寄生虫基因（GRXCR1）在小鼠内耳中也有选择地表达。使用分子遗传和细胞生物学方法，我们建议研究GRXCR1和GRXCR2的生化，细胞和生理作用。我们将确定这些蛋白质在内耳组织中的亚细胞定位（AIM 1），确定蛋白质在体外，培养的细胞和内耳组织外植体中所需的结构域，并检查这些活性的相互依存关系（AIM 2），确定可能与GRXCR1直接相互作用的其他蛋白质（AIM 3），并产生grxcr的势力图4的势力图4的势力（AIM）。通过这些目标，我们将研究立体胶质发育，肌动蛋白动力学和受还原/氧化途径影响的过程之间的潜在联系，从而深入了解感觉细胞发育和功能的分子控制。