Sánchez-Calderón Hortensia, Martín-Partido Gervasio, Hidalgo-Sánchez Matías
Departamento de Biología Celular, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz, Spain.
Gene Expr Patterns. 2004 Oct;4(6):659-69. doi: 10.1016/j.modgep.2004.04.008.
The chick inner ear is a complex structure containing auditory and vestibular sensory organs innervated by neurons of the acoustic-vestibular ganglion. The molecular signals involved in the specification and initial innervation of the otic epithelium are poorly understood. Here, we present a detailed description of the Otx2, Gbx2, and Fgf8 gene expression patterns in the chick developing inner ear, comparing them with the Bmp4 expression, a putative sensory-organ marker. The Otx2 expression was detected in the ventro-lateral wall of the otic anlage and could play a role in the segregation of the saccule and utricle maculae. The relationship between Gbx2 and Fgf8 expression changed during inner ear development but was always related to the macula sacculi innervation and endolymphatic duct formation. Our results also suggest that the maculae of the saccule and lagena, and the medial portion of the macula utriculi could arise within a broad Fgf8-positive domain previously observed at the otocyst stage. The spatial and temporal relationships between these gene expression domains and the initial innervation of the epithelium by some subpopulations of otic axons suggest that expression domain boundaries could be involved in the specification and early innervation of presumptive sensory patches.
鸡内耳是一个复杂的结构，包含由听神经-前庭神经节神经元支配的听觉和前庭感觉器官。目前对参与耳上皮细胞特化和初始神经支配的分子信号了解甚少。在这里，我们详细描述了鸡内耳发育过程中Otx2、Gbx2和Fgf8基因的表达模式，并将它们与假定的感觉器官标记物Bmp4的表达进行比较。在耳原基的腹侧壁检测到Otx2的表达，它可能在球囊和椭圆囊斑的分离中起作用。在耳蜗发育过程中，Gbx2和Fgf8的表达关系发生了变化，但始终与球囊斑神经支配和内淋巴管形成有关。我们的结果还表明，球囊和瓶状囊的斑以及椭圆囊斑的内侧部分可能出现在先前在耳泡阶段观察到的广泛的Fgf8阳性区域内。这些基因表达域与耳轴突的一些亚群对上皮的初始神经支配之间的时空关系表明，表达域边界可能参与了假定感觉斑的特化和早期神经支配。
