Xu Qiling, Wilkinson David G
Division of Developmental Neurobiology, MRC National Institute for Medical Research, London, UK.
Wiley Interdiscip Rev Dev Biol. 2013 Sep-Oct;2(5):735-45. doi: 10.1002/wdev.106. Epub 2013 Jan 25.
The formation of a sharp interface of adjacent subdivisions is important for establishing the precision of tissue organization, and at specific borders it serves to organize key signaling centers. We discuss studies of vertebrate hindbrain development that have given important insights into mechanisms that underlie the formation and maintenance of sharp borders. The hindbrain is subdivided into a series of segments with distinct anteroposterior identity that underlies the specification of distinct neuronal cell types. During early stages of segmentation, cell identity switching contributes to the refinement of borders and enables homogenous territories to be maintained despite intermingling of cells between segments. At later stages, there is a specific restriction to cell intermingling between segments that is mediated by Eph receptor and ephrin signaling. Eph-ephrin signaling can restrict cell intermingling and sharpen borders through multiple mechanisms, including the regulation of cell adhesion and contact inhibition of cell migration.
相邻亚区域形成清晰的边界对于建立组织构建的精确性很重要，并且在特定边界处，它有助于组织关键信号中心。我们讨论了脊椎动物后脑发育的研究，这些研究为清晰边界的形成和维持机制提供了重要见解。后脑被细分为一系列具有不同前后身份的节段，这是不同神经元细胞类型特化的基础。在分割的早期阶段，细胞身份转换有助于边界的细化，并使同质区域得以维持，尽管节段间细胞会相互混合。在后期阶段，节段间细胞混合存在特定限制，这是由Eph受体和ephrin信号介导的。Eph-ephrin信号可以通过多种机制限制细胞混合并锐化边界，包括调节细胞粘附和细胞迁移的接触抑制。
