Cruciani V, Mikalsen S-O
The Norwegian Radium Hospital, Institute for Cancer Research, 0310, Oslo, Norway.
Cell Mol Life Sci. 2006 May;63(10):1125-40. doi: 10.1007/s00018-005-5571-8.
Connexins are chordate-specific transmembrane proteins that can form gap junctional channels between adjacent cells. With the progress in vertebrate genome sequencing, it is now possible to reconstruct the main lines in the evolution of the connexin family from fishes to mammals. Four connexin groups are only found in fishes. Otherwise, the differences between fishes and mammals can be explained by two gene losses (Cx39.9 and Cx43.4) after the divergence of the Reptilia, and three gene duplications (the generation of Cx26 and 30 from a preCx26/30 sequence, Cx30.3 and 31.1 from a preCx30.3/ 31.1 sequence, and Cx31.3 from an uncertain origin). Orthologs of most connexins can be found throughout the vertebrates from fishes to mammals. As judged from the recently defined connexins in tunicates, the original connexin might be related to the ortholog groups of Cx36, 39.2, 43.4, 45 or 47.
连接蛋白是脊索动物特有的跨膜蛋白，可在相邻细胞之间形成间隙连接通道。随着脊椎动物基因组测序的进展，现在有可能重建从鱼类到哺乳动物的连接蛋白家族进化的主线。四个连接蛋白组仅在鱼类中发现。否则，鱼类和哺乳动物之间的差异可以通过爬行纲分化后的两次基因丢失（Cx39.9和Cx43.4）以及三次基因复制（由preCx26/30序列产生Cx26和30，由preCx30.3/31.1序列产生Cx30.3和31.1，以及起源不确定的Cx31.3）来解释。从鱼类到哺乳动物的整个脊椎动物中都可以找到大多数连接蛋白的直系同源物。从最近在被囊动物中定义的连接蛋白判断，原始连接蛋白可能与Cx36、39.2、43.4、45或47的直系同源物组有关。
