Vandekerckhove J, Weber K
J Mol Biol. 1984 Nov 5;179(3):391-413. doi: 10.1016/0022-2836(84)90072-x.
A total of 30 actins from various chordate and invertebrate muscle sources were either characterized by full amino acid sequence data or typed by those partial sequences in the NH2-terminal tryptic peptide which are known to be specific markers for different actin isoforms. The results show that most, if not all, invertebrate muscle actins are homologous to each other and to the isoforms recognized as vertebrate cytoplasmic actins. In contrast the actin forms typically found in muscle cells of warm-blooded vertebrates are noticeably different from invertebrate muscle actins and seem to have appeared in evolution already with the origin of chordates. During subsequent vertebrate evolution there has been a high degree of sequence conservation similar or stronger than that seen in histone H4. Urochordates, Cephalochordates and probably also Agnathes express only one type of muscle actin. Two types, a striated muscle-specific form and a smooth muscle form, are already observed in Chondrichthyes and Osteichthyes. Later in evolution, with the origin of reptiles, both muscle actins seem to have duplicated again; the striated muscle type branched into a skeletal- and cardiac-specific form, while the smooth muscle form duplicated into a vascular- and stomach-specific type. These findings support the hypothesis that each of the four muscle actins of warm-blooded vertebrates are coded for by a small number and possibly only one functional gene.
来自各种脊索动物和无脊椎动物肌肉来源的总共30种肌动蛋白，要么通过完整的氨基酸序列数据进行表征，要么通过已知是不同肌动蛋白异构体特异性标记的NH2末端胰蛋白酶肽中的那些部分序列进行分型。结果表明，大多数（如果不是全部）无脊椎动物肌肉肌动蛋白彼此同源，并且与被认为是脊椎动物细胞质肌动蛋白的异构体同源。相比之下，温血脊椎动物肌肉细胞中典型发现的肌动蛋白形式与无脊椎动物肌肉肌动蛋白明显不同，并且似乎在进化中已经随着脊索动物的起源而出现。在随后的脊椎动物进化过程中，存在高度的序列保守性，类似于或强于组蛋白H4中的序列保守性。尾索动物、头索动物以及可能还有无颌类动物只表达一种类型的肌肉肌动蛋白。在软骨鱼和硬骨鱼中已经观察到两种类型，一种是横纹肌特异性形式，另一种是平滑肌形式。在进化后期，随着爬行动物的起源，两种肌肉肌动蛋白似乎又发生了重复；横纹肌类型分支为骨骼和心脏特异性形式，而平滑肌形式重复为血管和胃特异性类型。这些发现支持了这样一种假设，即温血脊椎动物的四种肌肉肌动蛋白中的每一种都由少数几个，甚至可能只有一个功能基因编码。
