Grande M A, van der Kraan I, van Steensel B, Schul W, de Thé H, van der Voort H T, de Jong L, van Driel R
J Cell Biochem. 1996 Dec 1;63(3):280-91. doi: 10.1002/(sici)1097-4644(19961201)63:3<280::aid-jcb3>3.0.co;2-t.
The PML protein is a human growth suppressor concentrated in 10 to 20 nuclear bodies per nucleus (PML bodies). Disruption of the PML gene has been shown to be related to acute promyelocytic leukaemia (APL). To obtain information about the function of PML bodies we have investigated the 3D-distribution of PML bodies in the nucleus of T24 cells and compared it with the spatial distribution of a variety of other nuclear components, using fluorescence dual-labeling immunocytochemistry and confocal microscopy. Results show that PML bodies are not enriched in nascent RNA, the splicing component U2-snRNP, or transcription factors (glucocorticoid receptor, TFIIH, and E2F). These results show that PML bodies are not prominent sites of RNA synthesis or RNA splicing. We found that a large fraction of PML bodies (50 to 80%) is closely associated with DNA replication domains during exclusively middle-late S-phase. Furthermore, in most cells that we analysed we found at least one PML body was tightly associated with a coiled body. In the APL cell line NB4, the PML gene is fused with the RAR alpha gene due to a chromosomal rearrangement. PML bodies have disappeared and the PML antigen, i.e., PML and the PML-RAR fusion protein, is dispersed in a punctated pattern throughout the nucleoplasm. We showed that in NB4 cells the sites that are rich in PML antigen significantly colocalize with sites at which nascent RNA accumulates. This suggests that, in contrast to non-APL cells, in NB4 cells the PML antigen is associated with sites of transcription. The implications of these findings for the function of PML bodies are consistent with the idea that PML bodies are associated with specific genomic loci.
早幼粒细胞白血病（PML）蛋白是一种人类生长抑制因子，每个细胞核中有10到20个核体（PML体）。PML基因的破坏已被证明与急性早幼粒细胞白血病（APL）有关。为了获取有关PML体功能的信息，我们利用荧光双标记免疫细胞化学和共聚焦显微镜技术，研究了T24细胞核中PML体的三维分布，并将其与多种其他核成分的空间分布进行了比较。结果表明，PML体在新生RNA、剪接成分U2 - snRNP或转录因子（糖皮质激素受体、TFIIH和E2F）中并不富集。这些结果表明，PML体不是RNA合成或RNA剪接的显著位点。我们发现，在S期的中晚期，大部分PML体（50%至80%）与DNA复制区域紧密相关。此外，在我们分析的大多数细胞中，我们发现至少有一个PML体与卷曲体紧密相关。在APL细胞系NB4中，由于染色体重排，PML基因与RARα基因融合。PML体消失，PML抗原，即PML和PML - RAR融合蛋白，以点状模式分散在整个核质中。我们表明，在NB4细胞中，富含PML抗原的位点与新生RNA积累的位点显著共定位。这表明，与非APL细胞相比，在NB4细胞中，PML抗原与转录位点相关。这些发现对PML体功能的影响与PML体与特定基因组位点相关的观点一致。
