Kim S K, Hebrok M, Melton D A
Department of Molecular and Cellular Biology, and Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, USA.
Development. 1997 Nov;124(21):4243-52. doi: 10.1242/dev.124.21.4243.
The role of the notochord in inducing and patterning adjacent neural and mesodermal tissues is well established. We provide evidence that the notochord is also required for one of the earliest known steps in the development of the pancreas, an endodermally derived organ. At a developmental stage in chick embryos when the notochord touches the endoderm, removal of notochord eliminates subsequent expression of several markers of dorsal pancreas bud development, including insulin, glucagon and carboxypeptidase A. Pancreatic gene expression can be initiated and maintained in prepancreatic chick endoderm grown in vitro with notochord. Non-pancreatic endoderm, however, does not express pancreatic genes when recombined with the same notochord. The results suggest that the notochord provides a permissive signal to endoderm to specify pancreatic fate in a stepwise manner.
脊索在诱导相邻神经组织和中胚层组织并使其形成特定模式方面的作用已得到充分证实。我们提供的证据表明，对于胰腺（一种内胚层来源的器官）发育过程中最早已知的步骤之一，脊索也是必需的。在鸡胚发育阶段，当脊索接触内胚层时，去除脊索会消除背侧胰腺芽发育的几种标志物随后的表达，包括胰岛素、胰高血糖素和羧肽酶A。胰腺基因表达可以在体外与脊索一起培养的胰腺前鸡内胚层中启动并维持。然而，非胰腺内胚层与相同的脊索重组时不表达胰腺基因。结果表明，脊索向内胚层提供了一个许可信号，以逐步确定胰腺命运。
