Division of High Resolution Optical Microscopy, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany.
J Cell Sci. 2010 Feb 1;123(Pt 3):392-400. doi: 10.1242/jcs.053496.
Promyelocytic leukemia nuclear bodies (PML-NBs) are mobile subnuclear organelles formed by PML and Sp100 protein. They have been reported to have a role in transcription, DNA replication and repair, telomere lengthening, cell cycle control and tumor suppression. We have conducted high-resolution 4Pi fluorescence laser-scanning microscopy studies complemented with correlative electron microscopy and investigations of the accessibility of the PML-NB subcompartment. During interphase PML-NBs adopt a spherical organization characterized by the assembly of PML and Sp100 proteins into patches within a 50- to 100-nm-thick shell. This spherical shell of PML and Sp100 imposes little constraint to the exchange of components between the PML-NB interior and the nucleoplasm. Post-translational SUMO modifications, telomere repeats and heterochromatin protein 1 were found to localize in characteristic patterns with respect to PML and Sp100. From our findings, we derived a model that explains how the three-dimensional organization of PML-NBs serves to concentrate different biological activities while allowing for an efficient exchange of components.
早幼粒细胞白血病核体（PML-NBs）是由 PML 和 Sp100 蛋白形成的可移动的亚核细胞器。它们已被报道在转录、DNA 复制和修复、端粒延长、细胞周期控制和肿瘤抑制中发挥作用。我们进行了高分辨率 4Pi 荧光激光扫描显微镜研究，并辅以相关的电子显微镜研究和 PML-NB 亚区室可及性的研究。在间期中，PML-NBs 采用球形组织，其特征在于 PML 和 Sp100 蛋白组装成 50-100nm 厚壳内的斑块。PML 和 Sp100 的这个球形壳对 PML-NB 内部和核质之间的成分交换几乎没有限制。发现翻译后 SUMO 修饰物、端粒重复序列和异染色质蛋白 1 相对于 PML 和 Sp100 以特征性模式定位。根据我们的发现，我们得出了一个模型，解释了 PML-NBs 的三维组织如何集中不同的生物活性，同时允许成分的有效交换。
