ROLE OF TOPOISOMERASE-II IN THE STRUCTURAL AND FUNCTIONAL EVOLUTION OF MITOGEN-STIMULATED LYMPHOCYTE NUCLEI
ROLE OF TOPOISOMERASE-II IN THE STRUCTURAL AND FUNCTIONAL EVOLUTION OF MITOGEN-STIMULATED LYMPHOCYTE NUCLEI
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DOI：
10.1006/excr.1994.1265
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发表时间：
1994-09-01
影响因子：
3.7
通讯作者：
WALKER, PR
中科院分区：
文献类型：
--
作者：
DAEV, E;CHALY, N;WALKER, PR
为了研究DNA拓扑异构酶II（Topo II）在小鼠淋巴细胞的促有丝分裂活化中的作用，我们在整个刺激期间应用Topo II抑制剂VM 26，并监测淋巴细胞活化的形态和功能参数。在0.05和0.5 μ M之间的剂量下，细胞活力和细胞大小的通常增加几乎不受影响。然而，DNA合成，已经显着抑制在0.05 μ M，RNA合成抑制程度较低。光镜放射自显影显示，进入S期的细胞比例较小，每个S期细胞掺入较少的[H-3]胸苷。在免疫荧光研究中，核仁抗原原纤蛋白减少，虽然只有轻微的影响snRNP Sm抗原和内部组件标记的抗体PI 1观察。在电子显微镜水平，核仁重塑和染色质变得聚集。在高剂量的VM 26（5 μ M）下，细胞在所有测定的活化参数中显示出预期的高水平凋亡和强抑制。结果支持了这样的假设，即Topo II β同种型参与淋巴细胞活化的非常早期阶段，Topo II α同种型的功能对VM 26更敏感，是通过S期进展所需的。(C)1994年出版社出版。
To examine the role of DNA topoisomerase II (Topo II) in the mitogenic activation of mouse lymphocytes, we applied the Topo II inhibitor VM26 throughout the stimulation period and monitored morphological and functional parameters of lymphocyte activation. Cell viability and the usual increase in cell size were little affected at doses between 0.05 and 0.5 mu M. DNA synthesis, however, was already significantly inhibited at 0.05 mu M, with RNA synthesis inhibited to a lesser extent. Light microscope autoradiography showed that a smaller proportion of cells entered S phase, with each S phase cell incorporating less [H-3]thymidine. In immunofluorescence studies, the nucleolar antigen fibrillarin was reduced, although only minor effects on the snRNP Sm antigen and the internal component labeled by antibody PI1 were observed. At the electron microscope level, nucleoli were remodeled and chromatin became aggregated. At a high dose of VM26 (5 mu M), cells showed the expected high levels of apoptosis and strong inhibition in all activation parameters assayed. The results support the hypothesis that the Topo II beta isoform is involved in the very early phases of lymphocyte activation, with function of the Topo II alpha isoform, which is more sensitive to VM26, being required for progression through S phase. (C) 1994 Academic Press, Inc.