Bermingham-McDonogh Olivia, Oesterle Elizabeth C, Stone Jennifer S, Hume Clifford R, Huynh Huy M, Hayashi Toshinori
Virginia Merrill Bloedel Hearing Research Center and Department of Otolaryngology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
J Comp Neurol. 2006 May 10;496(2):172-86. doi: 10.1002/cne.20944.
We carried out an analysis of the expression of Prox1, a homeo-domain transcription factor, during mouse inner ear development with particular emphasis on the auditory system. Prox1 is expressed in the otocyst beginning at embryonic day (E)11, in the developing vestibular sensory patches. Expression is down regulated in maturing (myosin VIIA immunoreactive) vestibular hair cells and subsequently in the underlying support cell layer by E16.5. In the auditory sensory epithelium, Prox1 is initially expressed at embryonic day 14.5 in a narrow stripe of cells at the base of the cochlea. This stripe encompasses the full thickness of the sensory epithelium, including developing hair cells and support cells. Over the next several days the stripe of expression extends to the apex, and as the sensory epithelium differentiates Prox1 becomes restricted to a subset of support cells. Double labeling for Prox1 and cell-type-specific markers revealed that the outer hair cells transiently express Prox1. After E18, Prox1 protein is no longer detectable in hair cells, but it continues to be expressed in support cells for the rest of embryogenesis and into the second postnatal week. During this time, Prox1 is not expressed in all support cell types in the organ of Corti, but is restricted to developing Deiters' and pillar cells. The expression is maintained in these cells into the second week of postnatal life, at which time Prox1 is dynamically down regulated. These studies form a baseline from which we can analyze the role of Prox1 in vertebrate sensory development.
我们对同源结构域转录因子Prox1在小鼠内耳发育过程中的表达进行了分析，特别关注听觉系统。Prox1在胚胎第11天（E11）开始在内耳囊中表达，位于发育中的前庭感觉斑。在成熟的（肌球蛋白VIIA免疫反应性）前庭毛细胞中表达下调，随后在E16.5时在其下方的支持细胞层中表达下调。在听觉感觉上皮中，Prox1最初在胚胎第14.5天在耳蜗底部的一条狭窄细胞带中表达。这条带涵盖了感觉上皮的全层，包括发育中的毛细胞和支持细胞。在接下来的几天里，表达带延伸到顶端，随着感觉上皮的分化，Prox1局限于支持细胞的一个亚群。Prox1与细胞类型特异性标记物的双重标记显示，外毛细胞短暂表达Prox1。E18后，Prox1蛋白在毛细胞中不再可检测到，但在胚胎发育的其余阶段以及出生后第二周，它在支持细胞中持续表达。在此期间，Prox1并非在柯蒂氏器的所有支持细胞类型中表达，而是局限于发育中的Deiters细胞和柱细胞。这种表达在这些细胞中维持到出生后第二周，此时Prox1被动态下调。这些研究形成了一个基线，我们可以据此分析Prox1在脊椎动物感觉发育中的作用。
