MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Nat Commun. 2022 Jul 27;13(1):4342. doi: 10.1038/s41467-022-31192-9.
Innate immune responses rely on inducible gene expression programmes which, in contrast to steady-state transcription, are highly dependent on cohesin. Here we address transcriptional parameters underlying this cohesin-dependence by single-molecule RNA-FISH and single-cell RNA-sequencing. We show that inducible innate immune genes are regulated predominantly by an increase in the probability of active transcription, and that probabilities of enhancer and promoter transcription are coordinated. Cohesin has no major impact on the fraction of transcribed inducible enhancers, or the number of mature mRNAs produced per transcribing cell. Cohesin is, however, required for coupling the probabilities of enhancer and promoter transcription. Enhancer-promoter coupling may not be explained by spatial proximity alone, and at the model locus Il12b can be disrupted by selective inhibition of the cohesinopathy-associated BET bromodomain BD2. Our data identify discrete steps in enhancer-mediated inducible gene expression that differ in cohesin-dependence, and suggest that cohesin and BD2 may act on shared pathways.
先天免疫反应依赖于诱导型基因表达程序，与稳态转录相比，诱导型基因表达程序高度依赖于黏合蛋白。在这里，我们通过单分子 RNA-FISH 和单细胞 RNA 测序来研究这种黏合蛋白依赖性的转录参数。我们表明，诱导型先天免疫基因主要通过增加活跃转录的概率来调节，并且增强子和启动子转录的概率是协调的。黏合蛋白对转录的诱导增强子的分数或每个转录细胞产生的成熟 mRNA 的数量没有重大影响。然而，黏合蛋白对于增强子和启动子转录的概率耦合并起着关键作用。增强子-启动子偶联不能仅用空间接近度来解释，在模型基因 Il12b 中，可以通过选择性抑制黏合蛋白病相关 BET 溴结构域 BD2 来破坏增强子-启动子偶联。我们的数据确定了增强子介导的诱导型基因表达中的离散步骤，这些步骤在黏合蛋白依赖性方面存在差异，并表明黏合蛋白和 BD2 可能作用于共享途径。
