The DNA-mediated innate immune response underpins anti-microbial defenses and certain autoimmune diseases. Here we used immunoprecipitation, mass spectrometry, and RNA sequencing to identify a ribonuclear complex built around HEXIM1 and the long non-coding RNA NEAT1 that we dubbed the HEXIM1-DNA-PK-paraspeckle components-ribonucleoprotein complex (HDP-RNP). The HDP-RNP contains DNA-PK subunits (DNAPKc, Ku70, and Ku80) and paraspeckle proteins (SFPQ, NONO, PSPC1, RBM14, and MATRIN3). We show that binding of HEXIM1 to NEAT1 is required for its assembly. We further demonstrate that the HDP-RNP is required for the innate immune response to foreign DNA, through the cGAS-STING-IRF3 pathway. The HDP-RNP interacts with cGAS and its partner PQBP1, and their interaction is remodeled by foreign DNA. Remodeling leads to the release of paraspeckle proteins, recruitment of STING, and activation of DNAPKc and IRF3. Our study establishes the HDP-RNP as a key nuclear regulator of DNA-mediated activation of innate immune response through the cGAS-STING pathway.

DNA介导的先天免疫应答是抗微生物防御和某些自身免疫性疾病的基础。在这里，我们使用免疫沉淀，质谱和RNA测序来鉴定围绕HEXIM1和长非编码RNA NEAT1构建的核糖核酸复合物，我们将其称为HEXIM1-DNA-PK-副斑点成分-核糖核蛋白复合物（HDP-RNP）。HDP-RNP包含DNA-PK亚基（DNAPKc，Ku70和Ku80）和散斑蛋白（SFPQ，NONO，PSPC1，RBM14和MATRIN3）。我们显示HEXIM1到NEAT1的绑定是其组装所必需的。我们进一步证明，HDP-RNP是通过cGAS-STING-IRF3途径对外源DNA进行先天免疫应答所必需的。HDP-RNP与cGAS及其伙伴PQBP1相互作用，并且它们的相互作用被外源DNA重塑。重塑导致副斑点蛋白的释放，STING的募集，以及DNAPKc和IRF3的激活。我们的研究将HDP-RNP建立为通过cGAS-STING途径DNA介导的先天免疫应答激活的关键核调节剂。