Dynamics of Telomeres and Promyelocytic Leukemia Nuclear Bodies in a Telomerase-negative Human Cell Line
Dynamics of Telomeres and Promyelocytic Leukemia Nuclear Bodies in a Telomerase-negative Human Cell Line
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DOI：
10.1091/mbc.e08-02-0108
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发表时间：
2009-04-01
影响因子：
3.3
通讯作者：
Rippe, Karsten
中科院分区：
文献类型：
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作者：
Jegou, Thibaud;Chung, Inn;Rippe, Karsten
端粒酶阴性肿瘤细胞通过替代性端粒延长（ALT）机制维持其端粒。这个过程涉及端粒与早幼粒细胞白血病核小体（PML-NB）的关联。在这里，端粒和PML-NB的移动性以及它们的相互作用在人U2 OS骨肉瘤细胞中进行了研究，其中ALT途径是活跃的。构建了U2 OS细胞系，其具有稳定整合在染色体6 q、11 p和12 q的端粒附近的lac操纵基因重复序列。通过荧光显微镜的自发荧光LacI阻遏物绑定到lacO阵列的端粒迁移率在间期跟踪和端粒重复长度相关。一个受限的扩散模型推导出描述端粒在细胞核中的动力学的时间尺度从秒到小时。两个端粒组被确定为不同的核空间，他们可以访问。此外，还对PML-NB相对于端粒的易位及其与端粒的复合物进行了评价。基于这些研究，提出了一个模型，其中端粒的缩短导致流动性增加，这可能有助于端粒和PML-NB之间形成复合物。
Telomerase-negative tumor cells maintain their telomeres via an alternative lengthening of telomeres (ALT) mechanism. This process involves the association of telomeres with promyelocytic leukemia nuclear bodies (PML-NBs). Here, the mobility of both telomeres and PML-NBs as well as their interactions were studied in human U2OS osteosarcoma cells, in which the ALT pathway is active. A U2OS cell line was constructed that had lac operator repeats stably integrated adjacent to the telomeres of chromosomes 6q, 11p, and 12q. By fluorescence microscopy of autofluorescent LacI repressor bound to the lacO arrays the telomere mobility during interphase was traced and correlated with the telomere repeat length. A confined diffusion model was derived that describes telomere dynamics in the nucleus on the time scale from seconds to hours. Two telomere groups were identified that differed with respect to the nuclear space accessible to them. Furthermore, translocations of PML-NBs relative to telomeres and their complexes with telomeres were evaluated. Based on these studies, a model is proposed in which the shortening of telomeres results in an increased mobility that could facilitate the formation of complexes between telomeres and PML-NBs.