Otey C A, Kalnoski M H, Lessard J L, Bulinski J C
J Cell Biol. 1986 May;102(5):1726-37. doi: 10.1083/jcb.102.5.1726.
In many vertebrate nonmuscle cells, the microfilament subunit protein, actin, exists as two isoforms, called beta and gamma, whose sequences differ only in their amino-terminal regions. We have prepared a peptide antibody specifically reactive with the amino-terminal sequence of gamma actin. This antibody reacted with nonmuscle actin as determined by Western blots of SDS gels, and reacted with the gamma, but not the beta, nonmuscle actin isoform as shown by Western blots of isoelectric focusing gels. In immunofluorescence experiments, the gamma peptide antibody stained microfilament bundles, ruffled edges, and the contractile ring of a variety of cultured cells, including mouse L cells, which have previously been reported to contain only the beta actin isoform (Sakiyama, S., S. Fujimura, and H. Sakiyama, 1981, J. Biol. Chem., 256:31-33). Double immunofluorescence experiments using the gamma peptide antibody and an antibody reactive with all actin isoforms revealed no differences in isoform localization. Thus, at the level of resolution of light microscopy, we have detected the gamma actin isoform in all microfilament-containing structures in cultured cells, and have observed no subcellular sorting of the nonmuscle actin isoforms.
在许多脊椎动物的非肌肉细胞中，微丝亚基蛋白肌动蛋白以两种异构体形式存在，称为β和γ，它们的序列仅在氨基末端区域有所不同。我们制备了一种与γ肌动蛋白的氨基末端序列特异性反应的肽抗体。通过SDS凝胶的蛋白质免疫印迹法测定，该抗体与非肌肉肌动蛋白发生反应；通过等电聚焦凝胶的蛋白质免疫印迹法显示，该抗体与γ而非β非肌肉肌动蛋白异构体发生反应。在免疫荧光实验中，γ肽抗体对多种培养细胞的微丝束、皱襞边缘和收缩环进行了染色，包括小鼠L细胞，此前有报道称小鼠L细胞仅含有β肌动蛋白异构体（Sakiyama, S., S. Fujimura, and H. Sakiyama, 1981, J. Biol. Chem., 256:31 - 33）。使用γ肽抗体和与所有肌动蛋白异构体反应的抗体进行的双重免疫荧光实验显示，异构体定位没有差异。因此，在光学显微镜的分辨率水平上，我们在培养细胞中所有含微丝的结构中检测到了γ肌动蛋白异构体，并且未观察到非肌肉肌动蛋白异构体的亚细胞分选现象。
