Shiraishi I, Takamatsu T, Fujita S
Department of Pathology, Kyoto Prefectural University of Medicine, Japan.
Anat Embryol (Berl). 1993 Feb;187(2):115-20. doi: 10.1007/BF00171742.
It is not yet understood whether cell adhesion molecules play an active role in early cardiac morphogenesis or not. We present here the spatial and temporal expressions of N-cadherin and its relationships to actin filaments during looping (7- to 13-somite stages) of the chick embryonic heart tube observed by means of a confocal laser scanning microscope. Serial optical tomograms were obtained from the whole-mounted heart tubes stained with antibody to N-cadherin (fluorescein-conjugated) and phalloidin (rhodamine-conjugated). Three patterns of N-cadherin expression were observed during looping; a belt-like pattern, speckled pattern, and clumped pattern, corresponding to adhesion belt, nonjunctional cell contact and early intercalated disks, respectively. At the 7-somite stage, myocytes expressed N-cadherin as adhesion belt and nonjunctional cell contact. At the 8- to 10-somite stages, the clumped pattern of N-cadherin was detected before striated myofibrils appeared. Myofibrils began to develop across the clumps to form transcellular networks in the outer layer, and to form circumferential alignments in the inner layer. These results suggest that N-cadherin is responsible for the connection of myofibrils between the neighboring myocytes, and the alignment of the two layers in the developing heart tube.
细胞黏附分子在心脏早期形态发生过程中是否发挥积极作用尚不清楚。在此，我们通过共聚焦激光扫描显微镜观察了鸡胚心脏管在成环期（7至13体节期）N-钙黏着蛋白的时空表达及其与肌动蛋白丝的关系。从用抗N-钙黏着蛋白（荧光素偶联）抗体和鬼笔环肽（罗丹明偶联）染色的整装心脏管中获取连续光学断层图像。在成环过程中观察到N-钙黏着蛋白表达的三种模式；带状模式、斑点状模式和聚集模式，分别对应黏附带、非连接性细胞接触和早期闰盘。在7体节期，心肌细胞将N-钙黏着蛋白表达为黏附带和非连接性细胞接触。在8至10体节期，在横纹肌原纤维出现之前检测到N-钙黏着蛋白的聚集模式。肌原纤维开始穿过这些聚集物在外层形成跨细胞网络，并在内层形成圆周排列。这些结果表明，N-钙黏着蛋白负责相邻心肌细胞之间肌原纤维的连接以及发育中心脏管两层的排列。
