Sanger J M, Sanger J W
J Cell Biol. 1980 Aug;86(2):568-75. doi: 10.1083/jcb.86.2.568.
Heavy meromyosin (HMM) decoration of actin filaments was used to detect the polarity of microfilaments in interphase and cleaving rat kangaroo (PtK2) cells. Ethanol at -20 degrees C was used to make the cells permeable to HMM followed by tannic acid-glutaraldehyde fixation for electron microscopy. Uniform polarity of actin filaments was observed at cell junctions and central attachment plaques with the HMM arrowheads always pointing away from the junction or plaque. Stress fibers were banded in appearance with their component microfilaments exhibiting both parallel and antiparallel orientation with respect to one another. Identical banding of microfilament bundles was also seen in cleavage furrows with the same variation in filament polarity as found in stress fibers. Similarly banded fibers were not seen outside the cleavage furrow in mitotic cells. By the time that a mid-body was present, the actin filaments in the cleavage furrow were no longer in banded fibers. The alternating dark and light bands of both the stress fibers and cleavage furrow fibers are approximately equal in length, each measuring approximately 0.16 micrometer. Actin filaments were present in both bands, and individual decorated filaments could sometimes be traced through four band lengths. Undecorated filaments, 10 nm in diameter, could often be seen within the light bands. A model is proposed to explain the arrangement of filaments in stress fibers and cleavage furrows based on the striations observed with tannic acid and the polarity of the actin filaments.
用重酶解肌球蛋白（HMM）标记肌动蛋白丝来检测间期和分裂期大鼠袋鼠（PtK2）细胞中微丝的极性。使用-20℃的乙醇使细胞对HMM具有通透性，随后用单宁酸 - 戊二醛固定用于电子显微镜观察。在细胞连接处和中央附着斑观察到肌动蛋白丝的极性一致，HMM箭头始终指向远离连接处或斑块的方向。应力纤维外观呈带状，其组成微丝彼此呈现平行和反平行取向。在分裂沟中也观察到微丝束的相同带状结构，其丝极性变化与应力纤维中相同。在有丝分裂细胞的分裂沟外未见到类似带状的纤维。当出现中体时，分裂沟中的肌动蛋白丝不再呈带状纤维。应力纤维和分裂沟纤维的明暗交替带长度大致相等，每条带约为0.16微米。两条带中均存在肌动蛋白丝，有时可以追踪到单根被标记的丝穿过四个带长。在明带内经常可以看到直径为10nm的未被标记的丝。基于单宁酸观察到的条纹和肌动蛋白丝的极性，提出了一个模型来解释应力纤维和分裂沟中丝的排列。
