Insights into host–virus interactions during SARS-CoV-2 infection are needed to understand COVID-19 pathogenesis and may help to guide the design of novel antiviral therapeutics. N⁶-Methyladenosine modification (m⁶A), one of the most abundant cellular RNA modifications, regulates key processes in RNA metabolism during stress response. Gene expression profiles observed postinfection with different SARS-CoV-2 variants show changes in the expression of genes related to RNA catabolism, including m⁶A readers and erasers. We found that infection with SARS-CoV-2 variants causes a loss of m⁶A in cellular RNAs, whereas m⁶A is detected abundantly in viral RNA. METTL3, the m⁶A methyltransferase, shows an unusual cytoplasmic localization postinfection. The B.1.351 variant has a less-pronounced effect on METTL3 localization and loss of m⁶A than did the B.1 and B.1.1.7 variants. We also observed a loss of m⁶A upon SARS-CoV-2 infection in air/liquid interface cultures of human airway epithelia, confirming that m⁶A loss is characteristic of SARS-CoV-2-infected cells. Further, transcripts with m⁶A modification are preferentially down-regulated postinfection. Inhibition of the export protein XPO1 results in the restoration of METTL3 localization, recovery of m⁶A on cellular RNA, and increased mRNA expression. Stress granule formation, which is compromised by SARS-CoV-2 infection, is restored by XPO1 inhibition and accompanied by a reduced viral infection in vitro. Together, our study elucidates how SARS-CoV-2 inhibits the stress response and perturbs cellular gene expression in an m⁶A-dependent manner.

中文翻译：

---

感染不同 SARS-CoV-2 变体后细胞 m6A RNA 甲基化的全球丢失

需要深入了解 SARS-CoV-2 感染期间宿主与病毒的相互作用，以了解 COVID-19 的发病机制，并可能有助于指导新型抗病毒疗法的设计。N ⁶ -甲基腺苷修饰 (m ⁶ A) 是最丰富的细胞 RNA 修饰之一，在应激反应期间调节 RNA 代谢的关键过程。感染不同 SARS-CoV-2 变体后观察到的基因表达谱显示与 RNA 分解代谢相关的基因表达发生变化，包括 m ⁶ A 阅读器和擦除器。我们发现感染 SARS-CoV-2 变体会导致细胞 RNA 中的m ⁶ A丢失，而在病毒 RNA 中检测到大量的m ^{6 A。}METTL3，米⁶一种甲基转移酶，在感染后表现出异常的细胞质定位。与 B.1 和 B.1.1.7 变体相比， B.1.351 变体对 METTL3 定位和 m ⁶ A损失的影响不太明显。^{我们还在人气道上皮细胞的气/液界面培养物中观察到 SARS-CoV-2 感染后 m 6} A丢失，证实 m ⁶ A 丢失是 SARS-CoV-2 感染细胞的特征。此外，具有 m ⁶ A 修饰的转录本在感染后优先下调。输出蛋白 XPO1 的抑制导致 METTL3 定位的恢复，m ^6的恢复A 在细胞 RNA 上，并增加 mRNA 表达。受 SARS-CoV-2 感染影响的应激颗粒形成通过抑制 XPO1 得以恢复，并伴随着体外病毒感染的减少。^{总之，我们的研究阐明了 SARS-CoV-2 如何以 m 6} A 依赖性方式抑制应激反应并扰乱细胞基因表达。