G4解旋酶DHX36/G4R1的缺失会导致基因组不稳定,并调节癌细胞中的先天免疫基因表达。

Loss of DHX36/G4R1, a G4 resolvase, drives genome instability and regulates innate immune gene expression in cancer cells.

作者信息

Bartosik Anna R, Hou Pei-Chi, Tang Shangming, Vaughn James P, Smaldino Philip J, Ratan Aakrosh, Mayo Marty W, Wang Yuh-Hwa

机构信息

Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, United States.

NanoMedica LLC, Winston-Salem, NC 27106, United States.

出版信息

Nucleic Acids Res. 2025 Jun 20;53(12). doi: 10.1093/nar/gkaf621.

Abstract

G-quadruplexes (G4s) are four-stranded alternative secondary structures formed by guanine-rich nucleic acids and are prevalent across the human genome. G4s are enzymatically resolved by specialized helicases. Previous in vitro studies showed that DEAH-box helicase 36 (DHX36/G4R1/RHAU) has the highest specificity and affinity for G4 structures. Here, by mapping genome-wide DNA double-strand breaks (DSBs), we demonstrate that knockout of DHX36 helicase increases DSB enrichment at G4 sites and that the presence of the G4 motif is a significant mediator of genome instability at regulatory regions. The loss of DHX36 corresponds with the significant upregulation of NF-κB transcriptional programs, culminating in the production and secretion of proinflammatory cytokines. Loss of DHX36 expression results in the accumulation of cytoplasmic DNA fragments, an increase in the innate immune signaling stimulator of interferon response cGAMP interactor 1 (STING1) expression, and activation of genes involved in immune response pathways. Importantly, higher levels of DHX36 messenger RNA expression in human B-cell acute lymphoblastic leukemia correlate with improved overall survival relative to lower expression of DHX36, highlighting its critical role in preserving genome integrity at a cellular level and in the context of cancer.

摘要

G-四链体(G4s)是由富含鸟嘌呤的核酸形成的四链二级结构,在人类基因组中普遍存在。G4s由专门的解旋酶通过酶促作用解开。先前的体外研究表明,DEAH盒解旋酶36(DHX36/G4R1/RHAU)对G4结构具有最高的特异性和亲和力。在这里,通过绘制全基因组DNA双链断裂(DSB)图谱,我们证明敲除DHX36解旋酶会增加G4位点的DSB富集,并且G4基序的存在是调控区域基因组不稳定的重要介导因素。DHX36的缺失与NF-κB转录程序的显著上调相对应,最终导致促炎细胞因子的产生和分泌。DHX36表达的缺失导致细胞质DNA片段的积累,干扰素反应cGAMP相互作用因子1(STING1)表达的先天免疫信号刺激物增加,以及免疫反应途径相关基因的激活。重要的是,相对于DHX36较低的表达,人类B细胞急性淋巴细胞白血病中较高水平的DHX36信使RNA表达与总体生存率的提高相关,突出了其在细胞水平和癌症背景下维持基因组完整性的关键作用。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f105/12214017/96da15d7be48/gkaf621figgra1.jpg

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