Storti R V, Rich A
Proc Natl Acad Sci U S A. 1976 Jul;73(7):2346-50. doi: 10.1073/pnas.73.7.2346.
Actins isolated from embryonic chick brain and muscle differ in mobility when subjected to electrophoresis in gels containing urea and sodium dodecyl sulfate. Experiments were carried out to determine whether these actins are products of different structural genes and differ in primary amino acid sequence, or whether they are products of the same structural gene but are different because of post-translational modification. Messenger RNA from brain and muscle tissue was used to direct cell-free protein synthesis in wheat germ extracts. The synthesized actins were identified by conversion from globular to fibrous actin and by two-dimensional chromatographic analysis of tryptic peptides. The differences in electrophoretic mobility of brain compared to muscle actin were maintained in the cell-free protein synthetic products. Therefore, these mobility differences were not due to post-translational modification. It was concluded that brain and muscle actin are coded by different messenger RNAs and therefore arise from different structural genes. In addition, messenger RNA from 13- and 16-day embryonic thigh muscle directed the synthesis of both brain- and muscle-type actins, suggesting that muscle cell differentiation involves the regulation of at least two different actin genes.
从胚胎期鸡脑和肌肉中分离出的肌动蛋白，在含有尿素和十二烷基硫酸钠的凝胶中进行电泳时，迁移率有所不同。开展了实验以确定这些肌动蛋白是不同结构基因的产物且一级氨基酸序列存在差异，还是同一结构基因的产物但因翻译后修饰而有所不同。来自脑和肌肉组织的信使核糖核酸被用于指导小麦胚芽提取物中的无细胞蛋白质合成。通过从球状肌动蛋白转变为纤维状肌动蛋白以及对胰蛋白酶消化后的肽段进行二维色谱分析来鉴定合成的肌动蛋白。与肌肉肌动蛋白相比，脑肌动蛋白在电泳迁移率上的差异在无细胞蛋白质合成产物中依然存在。因此，这些迁移率差异并非由翻译后修饰导致。得出的结论是，脑肌动蛋白和肌肉肌动蛋白由不同的信使核糖核酸编码，因而源自不同的结构基因。此外，来自13日龄和16日龄胚胎大腿肌肉的信使核糖核酸指导合成了脑型和肌肉型肌动蛋白，这表明肌肉细胞分化涉及至少两个不同肌动蛋白基因的调控。
