Serras F, Damen P, Dictus W J A G, Notenboom R G E, Van den Biggelaar J A M
Department of Experimental Zoology, University of Utrecht, 3584, CH Utrecht, The Netherlands.
Rouxs Arch Dev Biol. 1989 Nov;198(4):191-200. doi: 10.1007/BF00375905.
Patterns of gap junctional communication in the ectoderm of embryos of Patella vulgata have been studied by intracellular injection of the fluorescent dye Lucifer Yellow, and by analysis of its subsequent spread to adjacent cells (dye-coupling). We found that dye-coupling became progressively restricted to different domains of the ectoderm, forming communication compartments. These communication compartments are characterized by their high coupling abilities within the compartment, and reduction of coupling across their boundaries. During development, the pretrochal (anterior) ectoderm becomes subdivided into two communication compartments, the apical organ and the anlage of the head ectoderm. The posttrochal (posterior) ectoderm becomes subdivided into different communication compartments in two successive phases. Firstly, in the 15-h embryo the dorsal and ventral domains of the ectoderm form separate communication compartments. A dorso-ventral communication boundary restricts the passage of dye between the two domains. Secondly, in the 24-h embryo dye-coupling becomes further compartmentalized in both the dorsal and ventral domains. These compartments correspond to the anlagen of different ectodermal structures. In order to study whether any level of coupling persists between the ectodermal compartments we injected currents through a microelectrode inserted into one cell of one compartment and monitored its spread by means of a second microelectrode inserted into one cell of another compartment (electrical coupling). Despite the absence of dye-coupling, electrical coupling between the ectodermal dye-coupling compartments was detected, which suggests that some level of communication is maintained between compartments. Our results demonstrate that within the ectoderm layer of Patella vulgata the transfer of dyes becomes progressively restricted to communication compartments and, concomitantly with the specification of the different ectodermal anlagen, these compartments become subdivided into smaller communication compartments.
通过向紫贻贝胚胎外胚层细胞内注射荧光染料路西法黄，并分析其随后向相邻细胞的扩散（染料偶联），对紫贻贝胚胎外胚层中的缝隙连接通讯模式进行了研究。我们发现染料偶联逐渐局限于外胚层的不同区域，形成通讯区室。这些通讯区室的特征是区内偶联能力高，而区界处偶联减少。在发育过程中，口前（前部）外胚层被细分为两个通讯区室，即顶器和头部外胚层原基。口后（后部）外胚层在两个连续阶段被细分为不同的通讯区室。首先，在15小时胚胎中，外胚层的背侧和腹侧区域形成独立的通讯区室。背腹通讯边界限制了染料在两个区域之间的传递。其次，在24小时胚胎中，染料偶联在背侧和腹侧区域进一步分区化。这些区室对应于不同外胚层结构的原基。为了研究外胚层区室之间是否存在任何水平的偶联，我们通过插入一个区室一个细胞的微电极注入电流，并通过插入另一个区室一个细胞的第二个微电极监测其扩散（电偶联）。尽管没有染料偶联，但检测到了外胚层染料偶联区室之间的电偶联，这表明区室之间维持了一定水平的通讯。我们的结果表明，在紫贻贝的外胚层内，染料的转移逐渐局限于通讯区室，并且随着不同外胚层原基的特化，这些区室进一步细分为更小的通讯区室。
