Miller S A, Adornato M, Briglin A, Cavanaugh M, Christian T, Jewett K, Michaelson C, Monoson T, Price F, Tignor J, Tyrell D
Department of Biology, Hamilton College, Clinton, NY 13323, USA.
Dev Dyn. 1999 Dec;216(4-5):398-410. doi: 10.1002/(SICI)1097-0177(199912)216:4/5<398::AID-DVDY8>3.0.CO;2-7.
A profile of proliferative growth assessed with tritium autoradiograms from White Leghorn embryo stages Hamburger-Hamilton 6-21 labeled in ovo presents evidence of hinged folding driven by localized differential cell proliferation in endoderm. There is a significant, bilateral pattern, and differences are most pronounced in axial levels that are folding and rotating. Highest proliferation is in cells producing folds; lowest proliferation is in median cells. Localized changes in cell shape are lacking, as are TUNEL markers and cell morphology that would suggest involvement of apoptosis. Folding endoderm to form gut tube appears to be a process that is driven by domains of high cell proliferation flanking a domain of significantly lower proliferation. When considered in the context of an epithelium attached to subjacent mesoderm, these differentials could produce a forced and directed buckling of endoderm into lateral folds that join and enclose a tube. Patterns suggest that endoderm folds about a median hinge. In the light of this new information, we suggest it is more precise to refine the term, median hinge point (MHP), to neural hinge point (NHP) and gut hinge point (GHP).
利用氚放射自显影片对处于汉密尔顿-汉堡分期6-21期的白来亨鸡胚在卵内进行标记，以此评估增殖性生长情况，结果显示内胚层中局部差异性细胞增殖驱动了铰链式折叠。存在显著的双侧模式，且在正在折叠和旋转的轴向水平差异最为明显。增殖最高的是产生褶皱的细胞；增殖最低的是中间细胞。缺乏细胞形状的局部变化，也没有表明凋亡参与的TUNEL标记和细胞形态。内胚层折叠形成肠管似乎是一个由高细胞增殖区域两侧显著较低增殖区域驱动的过程。当结合附着于下方中胚层的上皮组织来考虑时，这些差异可能导致内胚层被迫且定向地向内折叠形成侧褶，这些侧褶会合拢并围成一个管。模式表明内胚层围绕中间铰链折叠。鉴于这一新信息，我们建议将术语“中间铰链点（MHP）”更精确地细化为神经铰链点（NHP）和肠铰链点（GHP）。
