Factors Regulating Inner Ear Specification

调节内耳规格的因素

• 批准号: 7032780
• 负责人: Jean-Pierre Saint-Jeannet
• 金额: $ 26.95万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-14 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7032780
• 关键词: DNA binding protein; Wnt gene /protein; Xenopus; antisense nucleic acid; biological signal transduction; developmental genetics; embryogenesis; gene expression; genetic regulation; histology; labyrinth; nonmammalian vertebrate embryology; nucleoproteins; oligonucleotides; protein protein interaction; protein quantitation /detection; transcription factor; yeast two hybrid system

DESCRIPTION (provided by applicant): The vertebrate inner ear is a sensory organ implicated in hearing, balance and detection of acceleration. It develops from a thickening of the embryonic ectoderm known as the otic placode. Defining the molecular processes leading to specification of the otic placode is essential to understand inner ear development. Sox proteins comprise a large class of transcriptional regulators. One member of this family, Sox9, a well- established regulator of chondrogenesis and sex determination, is also one of the earliest genes expressed in the presumptive otic placode. Mutations in Sox9 result in campomelic dysplasia (CD), a fatal human disorder characterized by severe skeletal malformations and XY sex reversal. Reports of rare CD patients that survived indicate that they are also affected with sensorineural deafness, suggesting that Sox9 may play an important role in the development of the auditory system. We have shown that the otic expression of Sox9 in Xenopus is initiated early in the sensory layer of the ectoderm. In this tissue, Sox9 expression is regulated by Fgf and Wnt signaling and co-localizes with Pax8, one of the earliest gene expressed in response to otic placode inducing signals. Depletion of Sox9 protein in whole embryos using morpholino antisense oligonucleotides causes a dramatic loss of early and late otic markers, and in the most extreme cases these embryos fail to form a morphologically recognizable otic vesicle. The experiments below will test the following hypothesis: the transcription factor Sox9 is a key component of regulatory pathway required for inner ear specification. We propose: 1-To define the molecular regulators of Sox9 expression in the otic placode by establishing the origin of the signals activating Sox9 expression in the otic placode; and defining the requirement and sufficiency of Fgf and Wnt signaling for otic placode specification in whole embryos and animal explants. 2-To characterize the ear phenotype of Xenopus Sox9-deficient embryos 3-To identify Sox9-interacting partner molecules in the otic placode using a yeast two-hybrid screen, since Sox proteins are known to regulate their target genes through interaction with cell type-specific partner molecules.The characterization of such partner molecules should further our understanding of Sox9-mediated gene regulation in the context of the developing inner ear.

描述（由申请人提供）： 脊椎动物的内耳是一种感觉器官，涉及听觉、平衡和加速度检测。它是由称为耳基板的胚胎外胚层增厚而形成的。明确导致耳基板特化的分子过程对于理解内耳发育至关重要。Sox蛋白包括一大类转录调节因子。该家族的一个成员Sox 9是软骨形成和性别决定的公认调节因子，也是在推定的耳基板中表达的最早的基因之一。Sox 9突变导致肢端发育不良（CD），这是一种以严重骨骼畸形和XY性逆转为特征的致命人类疾病。罕见的CD患者存活的报告表明，他们也受到感音神经性耳聋的影响，这表明Sox 9可能在听觉系统的发育中发挥重要作用。我们已经表明，耳表达的Sox 9在爪蟾的外胚层的感觉层的早期启动。在该组织中，Sox 9表达受Fgf和Wnt信号传导调节，并且与Pax 8共定位，Pax 8是响应于耳基板诱导信号而表达的最早基因之一。使用吗啉代反义寡核苷酸在整个胚胎中耗尽Sox 9蛋白会导致早期和晚期耳标记物的急剧损失，并且在最极端的情况下，这些胚胎无法形成形态学上可识别的耳泡。下面的实验将检验以下假设：转录因子Sox 9是内耳特化所需的调控途径的关键组分。我们建议：1-通过建立激活耳基板中Sox 9表达的信号的来源来定义耳基板中Sox 9表达的分子调节剂;并定义完整胚胎和动物外植体中耳基板特化的Fgf和Wnt信号传导的要求和充分性。2-描述非洲爪蟾Sox 9缺陷胚胎的耳表型3-使用酵母双杂交筛选鉴定耳基板中的Sox 9相互作用伴侣分子，因为已知Sox蛋白通过与细胞类型特异性伴侣分子相互作用来调节其靶基因。