Segura M, Saborío J L
J Biol Chem. 1982 Aug 10;257(15):8867-71.
The fractionation of gizzard tropomyosin from 17-day-old chick embryos by electrophoresis in polyacrylamide gels indicates that this protein is composed of three different polypeptides that were designated as alpha, beta, and gamma. Each one of these polypeptides is resolved into two components with different isoelectric points when tropomyosin is fractionated by two-dimensional electrophoresis; the major components were designated as tropomyosins alpha 1, beta 1, and gamma 1 and the minor ones as tropomyosins alpha 2, beta 2, and gamma 2. The results of in vitro translation of gizzard RNA indicate that only tropomyosins alpha 1, beta 1, and gamma 1 are synthesized in the cell-free system. A partial separation of the mRNAs coding for tropomyosins alpha 1 and gamma 1 was obtained by fractionation of gizzard RNA by zonal centrifugation in sucrose gradients. Altogether these results indicate that in gizzard tissue from 17-day-old chick embryos three genes coding for different forms of tropomyosin are expressed.
通过在聚丙烯酰胺凝胶中进行电泳，对17日龄鸡胚的肌胃原肌球蛋白进行分级分离，结果表明该蛋白质由三种不同的多肽组成，分别命名为α、β和γ。当原肌球蛋白通过双向电泳进行分级分离时，这些多肽中的每一种又可进一步分为两个具有不同等电点的组分；主要组分被命名为原肌球蛋白α1、β1和γ1，次要组分则为原肌球蛋白α2、β2和γ2。肌胃RNA体外翻译的结果表明，在无细胞体系中仅合成了原肌球蛋白α1、β1和γ1。通过在蔗糖梯度中进行区带离心对肌胃RNA进行分级分离，实现了对编码原肌球蛋白α1和γ1的mRNA的部分分离。这些结果共同表明，在17日龄鸡胚的肌胃组织中，有三个编码不同形式原肌球蛋白的基因得以表达。
