Brown C R, Doxsey S J, White E, Welch W J
Department of Medicine, University of California, San Francisco 94143-0854.
J Cell Physiol. 1994 Jul;160(1):47-60. doi: 10.1002/jcp.1041600107.
Human 293 cells, transformed by and expressing the early region of the adenovirus genome (i.e., E1A and E1B), contain a phase-dense cytoplasmic structure situated in close proximity to the nucleus. Via indirect immunofluorescence studies such structures have been previously shown to contain both the adenovirus E1B (55 kDa) protein as well as the tumor suppressor gene product p53. Here we show that such structures also stain positive for the cytoplasmic hsp 70 proteins. Such phase-dense structures containing hsp 70, p53, and adenovirus E1B are not unique to 293 cells but also are observed in rodent cell lines stabily transfected with the early region of the adenovirus genome. Using an antibody against a centrosomal protein, pericentrin, we show that these cytoplasmic phase-dense structures are in close proximity to the centrosome. Cell fractionation studies revealed such structures to be highly detergent insoluble. However, like the centrosome, the cytoplasmic phase-dense structures could be rendered detergent soluble following treatment of the cells with agents that disrupt the integrity of the cytoskeleton. While the phase-dense structures appear in close proximity to the centrosome in interphase cells, during mitosis the centrosome and the phase-dense bodies separate from one another. Owing to these observations we examined whether hsp70 and p53 might also co-localize with the centrosome in other cell types not expressing the adenovirus E1A/E1B proteins. We show that a portion of both hsp70 and p53 indeed are present within the centrosome in Hela, COS, and 3T3 cells. These observations raise the possibility that components like hsp70 and p53 may participate in the mechanism(s) controlling cell division in mammalian cells.
由腺病毒基因组早期区域（即E1A和E1B）转化并表达的人293细胞，含有一种位于细胞核附近的嗜碱性细胞质结构。通过间接免疫荧光研究，先前已证明此类结构既含有腺病毒E1B（55 kDa）蛋白，也含有肿瘤抑制基因产物p53。在此我们表明，此类结构对细胞质热休克蛋白70（hsp 70）也呈阳性染色。此类含有hsp 70、p53和腺病毒E1B的嗜碱性结构并非293细胞所特有，在稳定转染了腺病毒基因组早期区域的啮齿动物细胞系中也能观察到。使用针对中心体蛋白中心粒外周蛋白的抗体，我们发现这些细胞质嗜碱性结构与中心体紧邻。细胞分级分离研究表明此类结构高度不溶于去污剂。然而，与中心体一样，在用破坏细胞骨架完整性的试剂处理细胞后，细胞质嗜碱性结构可变得可溶于去污剂。虽然在间期细胞中嗜碱性结构似乎紧邻中心体，但在有丝分裂期间，中心体和嗜碱性小体彼此分离。基于这些观察结果，我们研究了hsp70和p53在不表达腺病毒E1A/E1B蛋白的其他细胞类型中是否也可能与中心体共定位。我们发现，在Hela、COS和3T3细胞中，hsp70和p53的一部分确实存在于中心体内。这些观察结果增加了hsp70和p53等成分可能参与哺乳动物细胞中控制细胞分裂机制的可能性。
