Miyazaki J, Hosoya M, Ishimoda-Takagi T, Hirabayashi T
Institute of Biological Science, University of Tsukuba, Toaraki.
J Biochem. 1990 Jul;108(1):59-65. doi: 10.1093/oxfordjournals.jbchem.a123163.
The molecular heterogeneity and tissue specificity of crustacean tropomyosin were investigated, using muscle and nonmuscle tissues from the crayfish, Cambarus clarki. In muscle, three types of tropomyosin isoforms were found on two-dimensional gel electrophoresis. One of them was specific to cardiac muscle, and the other two were shared by skeletal and visceral muscles. In nonmuscle tissues, four types of isoforms were found on two-dimensional gel electrophoresis and in immunoreplica tests using an antiserum against crayfish skeletal muscle tropomyosin. Two of them were common to the muscle isoforms, but the other two were not detected in muscles. Furthermore, nonmuscle tissues contained several peculiar isoforms, the electrophoretic mobilities of which were considerably higher than those of the other isoforms mentioned above. When tropomyosin was purified from the mid-gut gland, these isoforms with high mobilities were found in the crude tropomyosin preparation. These results showed that the crayfish tropomyosin was heterogeneous and that the isoforms were distributed in a tissue-specific manner, like vertebrate tropomyosin. However, the results did not coincide with those of our previous study on horseshoe crab tropomyosin, which showed molecular heterogeneity but no tissue specificity. In view of the difference in the isoform distributions between the two major groups (Crustacea and Merostomata) of Arthropoda, the significance of the tissue specificity of tropomyosin isoforms was discussed.
利用克氏原螯虾（Cambarus clarki）的肌肉和非肌肉组织，研究了甲壳类原肌球蛋白的分子异质性和组织特异性。在肌肉组织中，二维凝胶电泳显示存在三种类型的原肌球蛋白同工型。其中一种是心肌特有的，另外两种存在于骨骼肌和内脏肌中。在非肌肉组织中，二维凝胶电泳以及使用抗克氏原螯虾骨骼肌原肌球蛋白抗血清的免疫印迹试验显示存在四种同工型。其中两种与肌肉同工型相同，但另外两种在肌肉中未检测到。此外，非肌肉组织含有几种特殊的同工型，其电泳迁移率明显高于上述其他同工型。从中肠腺纯化原肌球蛋白时，在粗制原肌球蛋白制剂中发现了这些高迁移率的同工型。这些结果表明，克氏原螯虾原肌球蛋白具有异质性，并且同工型以组织特异性方式分布，类似于脊椎动物的原肌球蛋白。然而，这些结果与我们之前对鲎原肌球蛋白的研究结果不一致，之前的研究显示存在分子异质性但无组织特异性。鉴于节肢动物两个主要类群（甲壳纲和肢口纲）之间同工型分布的差异，讨论了原肌球蛋白同工型组织特异性的意义。
