Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Dermatology, Duke University Medical Center, Durham, NC 27710, USA.
Cell Rep. 2018 Feb 20;22(8):2026-2038. doi: 10.1016/j.celrep.2018.01.084.
The spine is a segmented axial structure made of alternating vertebral bodies (centra) and intervertebral discs (IVDs) assembled around the notochord. Here, we show that, prior to centra formation, the outer epithelial cell layer of the zebrafish notochord, the sheath, segments into alternating domains corresponding to the prospective centra and IVD areas. This process occurs sequentially in an anteroposterior direction via the activation of Notch signaling in alternating segments of the sheath, which transition from cartilaginous to mineralizing domains. Subsequently, osteoblasts are recruited to the mineralized domains of the notochord sheath to form mature centra. Tissue-specific manipulation of Notch signaling in sheath cells produces notochord segmentation defects that are mirrored in the spine. Together, our findings demonstrate that notochord sheath segmentation provides a template for vertebral patterning in the zebrafish spine.
脊柱是由交替的椎体（中心）和椎间盘（IVD）组成的分段轴向结构，围绕脊索组装。在这里，我们表明，在中心形成之前，斑马鱼脊索的外上皮细胞层，鞘，分段成与预期的中心和 IVD 区域相对应的交替域。这个过程通过鞘的交替节段中 Notch 信号的激活，以前后方向顺序发生，鞘从软骨转化为矿化区域。随后，成骨细胞被募集到脊索鞘的矿化区域形成成熟的中心。鞘细胞中 Notch 信号的组织特异性操作会产生脊索分段缺陷，这在脊柱中得到了反映。总之，我们的发现表明，脊索鞘的分段为斑马鱼脊柱的椎体模式提供了模板。
