Bruzzone R, Haefliger J A, Gimlich R L, Paul D L
Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts 02115.
Mol Biol Cell. 1993 Jan;4(1):7-20. doi: 10.1091/mbc.4.1.7.
The cellular distribution of connexin40 (Cx40), a newly cloned gap junction structural protein, was examined by immunofluorescence microscopy using two different specific anti-peptide antibodies. Cx40 was detected in the endothelium of muscular as well as elastic arteries in a punctate pattern consistent with the known distribution of gap junctions. However, it was not detected in other cells of the vascular wall. By contrast, Cx43, another connexin present in the cardiovascular system, was not detected in endothelial cells of muscular arteries but was abundant in the myocardium and aortic smooth muscle. We have tested the ability of these connexins to interact functionally. Cx40 was functionally expressed in pairs of Xenopus oocytes and induced the formation of intercellular channels with unique voltage dependence. Unexpectedly, communication did not occur when oocytes expressing Cx40 were paired with those expressing Cx43, although each could interact with a different connexin, Cx37, to form gap junction channels in paired oocytes. These findings indicate that establishment of intercellular communication can be spatially regulated by the selective expression of different connexins and suggest a mechanism that may operate to control the extent of communication between cells.
采用两种不同的特异性抗肽抗体，通过免疫荧光显微镜检查新克隆的缝隙连接结构蛋白连接蛋白40（Cx40）的细胞分布。在肌性动脉和弹性动脉的内皮中检测到Cx40，呈点状分布，与已知的缝隙连接分布一致。然而，在血管壁的其他细胞中未检测到。相比之下，心血管系统中存在的另一种连接蛋白Cx43，在肌性动脉的内皮细胞中未检测到，但在心肌和主动脉平滑肌中大量存在。我们测试了这些连接蛋白在功能上相互作用的能力。Cx40在非洲爪蟾卵母细胞对中功能性表达，并诱导形成具有独特电压依赖性的细胞间通道。出乎意料的是，当表达Cx40的卵母细胞与表达Cx43的卵母细胞配对时，并未发生通讯，尽管它们各自都能与不同的连接蛋白Cx37相互作用，在配对的卵母细胞中形成缝隙连接通道。这些发现表明，细胞间通讯的建立可通过不同连接蛋白的选择性表达在空间上进行调节，并提示了一种可能用于控制细胞间通讯程度的机制。
