磷脂酰肌醇磷酸酯是强大的信号分子,可协调信号传导并指导胞质溶胶中的膜运输。有趣的是,磷脂酰肌醇磷酸酯也位于细胞核的无膜隔室中,它们参与基因表达的调节。然而,目前的基因表达模型,其中包括蛋白质和核酸的凝聚物,不包括核磷脂酰肌醇磷酸酯。这种差距部分是由于缺少对磷脂酰肌醇磷酸酯的亚核分布及其与基因表达关系的详细分析。这里,我们使用定量双色直接随机光学重建显微镜来分析RNA聚合酶II转录起始标记和延伸标记之间相对于核质和核斑点中磷脂酰肌醇4,5-或3,4-二磷酸的纳米级共模式,并将其与随机数据和转录抑制的细胞进行比较。我们发现转录起始标记P-S5与核质中的磷脂酰肌醇4,5-二磷酸以及核斑点周围的磷脂酰肌醇3,4-二磷酸的特异性共模式。我们显示了转录延伸标记PS-2和新生RNA在与核斑点相关的磷脂酰肌醇3,4-二磷酸附近的特异性积累。一起来看,这表明RNA聚合酶II转录的连续阶段与磷脂酰肌醇磷酸的连续阶段之间的不同空间关联在基因表达区室内表现出特异性.因此,类似于细胞膜,磷脂成分协调信号通路并指导膜运输,我们提出了一个模型,其中基因表达区室的磷脂身份协调RNA聚合酶II转录。
Phosphatidylinositol phosphates are powerful signaling molecules that orchestrate signaling and direct membrane trafficking in the cytosol. Interestingly, phosphatidylinositol phosphates also localize within the membrane-less compartments of the cell nucleus, where they participate in the regulation of gene expression. Nevertheless, current models of gene expression, which include condensates of proteins and nucleic acids, do not include nuclear phosphatidylinositol phosphates. This gap is partly a result of the missing detailed analysis of the subnuclear distribution of phosphatidylinositol phosphates and their relationships with gene expression. Here, we used quantitative dual-color direct stochastic optical reconstruction microscopy to analyze the nanoscale co-patterning between RNA polymerase II transcription initiation and elongation markers with respect to phosphatidylinositol 4,5- or 3,4-bisphosphate in the
nucleoplasm and nuclear speckles and compared it with randomized data and cells with inhibited transcription. We found specific co-patterning of the transcription initiation marker P-S5 with phosphatidylinositol 4,5-bisphosphate in the
nucleoplasm and with phosphatidylinositol 3,4-bisphosphate at the periphery of nuclear speckles. We showed the specific accumulation of the transcription elongation marker PS-2 and of nascent RNA in the proximity of phosphatidylinositol 3,4-bisphosphate associated with nuclear speckles. Taken together, this shows that the distinct spatial associations between the consecutive stages of RNA polymerase II transcription and nuclear phosphatidylinositol phosphates exhibit specificity within the gene expression compartments. Thus, in analogy to the cellular membranes, where phospholipid composition orchestrates signaling pathways and directs membrane trafficking, we propose a model in which the phospholipid identity of gene expression compartments orchestrates RNA polymerase II transcription.