Owaribe K, Masuda H
J Cell Biol. 1982 Oct;95(1):310-5. doi: 10.1083/jcb.95.1.310.
Chicken retinal pigmented epithelial cells have circumferential microfilament bundles (CMBs) at the zonula adherens region. We have isolated these CMBs in intact form and characterized them structurally and biochemically. Pigmented epithelia obtained from 11-d-old chick embryos were treated with glycerol and Triton. Then, the epithelia were homogenized by passing them through syringe needles. Many isolated CMBs were found in the homogenate by phase-contrast microscopy. They formed polygons, mostly pentagons and hexagons, or fragments of polygons. Polygons were filled with meshwork structures, i.e. they were polygonal plates. Upon exposure to Mg-ATP, isolated CMBs showed clear and large contraction. The contraction was inhibited by treatment with N-ethylmaleimide-modified myosin subfragment-1. After purification by centrifugation with the density gradient of Percoll, CMBs were analyzed by SDS PAGE. The electrophoretic pattern gave three major components of 200, 55, and 42 kdaltons and several minor components. Electron microscopy showed that the polygons were composed of thick bundles of actin-containing microfilaments, and the meshworks were composed primarily of intermediate filaments.
鸡视网膜色素上皮细胞在紧密连接区域有周向微丝束（CMBs）。我们已完整分离出这些CMBs，并对其进行了结构和生化特性分析。从11日龄鸡胚获得的色素上皮用甘油和曲拉通处理。然后，通过注射器针头将上皮匀浆。通过相差显微镜在匀浆中发现了许多分离的CMBs。它们形成多边形，大多为五边形和六边形，或多边形片段。多边形内部充满网状结构，即它们是多边形板。暴露于Mg-ATP后，分离的CMBs显示出明显且大幅度的收缩。用N-乙基马来酰亚胺修饰的肌球蛋白亚片段-1处理可抑制这种收缩。用Percoll密度梯度离心法纯化后，通过SDS-PAGE对CMBs进行分析。电泳图谱给出了三个主要成分，分子量分别为200、55和42千道尔顿，以及几个次要成分。电子显微镜显示，多边形由含肌动蛋白的粗微丝束组成，而网状结构主要由中间丝组成。
