Williams N E, Honts J E, Jaeckel-Williams R F
Department of Biology, University of Iowa, Iowa City 52242.
J Cell Sci. 1987 Apr;87 ( Pt 3):457-63. doi: 10.1242/jcs.87.3.457.
Antisera have been raised in rabbits against three high molecular weight proteins that are present in Triton X-100-insoluble residues of Tetrahymena pyriformis GL cells. These proteins, called A, B and C, have apparent molecular weights of 235, 135 and 125 (X 10(3)), respectively, in SDS-polyacrylamide gels. The antisera obtained are specific for these proteins, as shown by immunoblotting. Immunolocalization studies are reported that suggest that these proteins are present throughout the epiplasmic layer beneath the cell surface (membrane skeleton). Images obtained with the fluorescence microscope, however, suggest that the membrane skeleton is modified in discrete zones: (1) around somatic basal bodies, (2) within the oral apparatus, (3) in the cytoproct, (4) in contractile vacuole pores, (5) in the fission zone in late division, and (6) at the mating junction in conjugating cells. These regions may represent areas of increased rigidity at the cell surface. The transition from pliable to rigid epiplasm in spatially delimited areas is apparently a recurring theme in cortical morphogenesis in Tetrahymena. Together, the two types of epiplasm probably allow for extensive changes in cell shape while preserving essential relationships between structural elements within the cortex.
已用兔制备了针对三种高分子量蛋白质的抗血清，这三种蛋白质存在于梨形四膜虫GL细胞的Triton X - 100不溶性残渣中。在SDS - 聚丙烯酰胺凝胶中，这些分别称为A、B和C的蛋白质的表观分子量分别为235、135和125（×10³）。如免疫印迹所示，所获得的抗血清对这些蛋白质具有特异性。报道了免疫定位研究，结果表明这些蛋白质存在于细胞表面（膜骨架）下方的整个表质层中。然而，用荧光显微镜获得的图像表明，膜骨架在离散区域发生了改变：（1）围绕体细胞基体；（2）在口器内；（3）在胞肛处；（4）在收缩泡孔中；（5）在后期分裂的分裂区；（6）在接合细胞的交配连接处。这些区域可能代表细胞表面刚性增加的区域。在空间上界定的区域中，从柔韧的表质到刚性表质的转变显然是四膜虫皮层形态发生中反复出现的主题。这两种表质类型可能共同允许细胞形状发生广泛变化，同时保持皮层内结构元件之间的基本关系。
