A genomewide survey of developmentally relevant genes in Ciona intestinalis -: X.: Genes for cell junctions and extracellular matrix
A genomewide survey of developmentally relevant genes in Ciona intestinalis -: X.: Genes for cell junctions and extracellular matrix
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DOI：
10.1007/s00427-003-0320-1
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发表时间：
2003-06-01
影响因子：
2.4
通讯作者：
Satoh, N
中科院分区：
文献类型：
--
作者：
Sasakura, Y;Shoguchi, E;Satoh, N
细胞连接和细胞外基质（ECM）是细胞间通讯的重要组成部分。这些系统被认为在脊椎动物进化过程中变得高度多样化。在本研究中，我们已经检查了祖先脊索动物是否已经有这样的脊椎动物系统的细胞间通信，我们已经搜索了海鞘玻璃海鞘的基因组。从这个分子的角度来看，玻璃海鞘基因组含有编码紧密连接、半桥粒和基于连接蛋白的间隙连接的蛋白质组分的基因。以及粘附连接和局灶性粘附，但没有桥粒。后者的遗漏是奇怪的，海鞘I型钙粘蛋白可能代表脊椎动物I型钙粘蛋白和桥粒钙粘蛋白的祖先形式，而Ci-Plakin可能代表脊椎动物桥粒斑蛋白和plectins的祖先蛋白。如果是这样，那么海鞘可能保留了祖先的桥粒样结构。正如先前的电子显微镜观察所示。此外，在玻璃海鞘基因组中也发现了被认为是脊椎动物特异性的ECM基因。这些结果表明，海鞘和脊椎动物共享的最后一个共同祖先，整个脊索动物分支的祖先，具有与现存脊椎动物基本相同的细胞连接系统。然而，玻璃海鞘基因组中每个家族的此类基因的数量远小于脊椎动物基因组中的基因数量。在脊椎动物中，这些祖先细胞连接似乎已经进化成更多样化，可能更复杂的形式，与它们的兄弟姐妹相比。
Cell junctions and the extracellular matrix (ECM) are crucial components in intercellular communication. These systems are thought to have become highly diversified during the course of vertebrate evolution. In the present study, we have examined whether the ancestral chordate already had such vertebrate systems for intercellular communication, for which we have searched the genome of the ascidian Ciona intestinalis. From this molecular perspective, the Ciona genome contains genes that encode protein components of tight junctions, hemidesmosomes and connexin-based gap junctions. as well as of adherens junctions and focal adhesions, but it does not have those for desmosomes. The latter omission is curious, and the ascidian type-I cadherins may represent an ancestral form of the vertebrate type-I cadherins and desmosomal cadherins, while Ci-Plakin may represent an ancestral protein of the vertebrate desmoplakins and plectins. If this is the case, then ascidians may have retained ancestral desmosome-like structures. as suggested by previous electron-microscopic observations. In addition, ECM genes that have been regarded as vertebrate-specific were also found in the Ciona genome. These results suggest that the last common ancestor shared by ascidians and vertebrates, the ancestor of the entire chordate clade, had essentially the same systems of cell junctions as those in extant vertebrates. However, the number of such genes for each family in the Ciona genome is far smaller than that in vertebrate genomes. In vertebrates these ancestral cell junctions appear to have evolved into more diverse, and possibly more complex, forms, compared with those in their urochordate siblings.