N6-甲基腺苷 (m6A) 修饰在 RNA 代谢中发挥着至关重要的作用。 m6A 如何调节 RNA 聚合酶 II (RNA Pol II) 转录仍不清楚。我们发现 7SK 小核 RNA (snRNA)（RNA Pol II 启动子近端暂停的调节因子）在非小细胞肺癌 (NSCLC) 细胞中经过高度 m6A 修饰。在 A549 细胞中，我们鉴定了 7SK 上的 8 个 m6A 位点，并发现甲基转移酶样 3 (METTL3) 和 alkB 同源物 5 (ALKBH5) 作为负责的写入器和擦除器。当 m6A-7SK 被 dCasRx-ALKBH5 融合蛋白特异性擦除时，A549 细胞生长由于 RNA Pol II 转录减少而减弱。从机制上讲，去除 m6A 会导致 7SK 结构重排，从而促进正转录延伸因子 b (P-TEFb) 复合物的隔离，从而导致 RNA Pol II C 末端结构域中丝氨酸 2 磷酸化 (Ser2P) 的减少以及RNA Pol II 位于启动子近端区域。综上所述，我们发现非编码 RNA 的 m6A 修饰可调节 RNA Pol II 转录和 NSCLC 肿瘤发生。版权所有 © 2023 Elsevier Inc. 保留所有权利。

N6-methyladenosine (m6A) modifications play crucial roles in RNA metabolism. How m6A regulates RNA polymerase II (RNA Pol II) transcription remains unclear. We find that 7SK small nuclear RNA (snRNA), a regulator of RNA Pol II promoter-proximal pausing, is highly m6A-modified in non-small cell lung cancer (NSCLC) cells. In A549 cells, we identified eight m6A sites on 7SK and discovered methyltransferase-like 3 (METTL3) and alkB homolog 5 (ALKBH5) as the responsible writer and eraser. When the m6A-7SK is specifically erased by a dCasRx-ALKBH5 fusion protein, A549 cell growth is attenuated due to reduction of RNA Pol II transcription. Mechanistically, removal of m6A leads to 7SK structural rearrangements that facilitate sequestration of the positive transcription elongation factor b (P-TEFb) complex, which results in reduction of serine 2 phosphorylation (Ser2P) in the RNA Pol II C-terminal domain and accumulation of RNA Pol II in the promoter-proximal region. Taken together, we uncover that m6A modifications of a non-coding RNA regulate RNA Pol II transcription and NSCLC tumorigenesis.Copyright © 2023 Elsevier Inc. All rights reserved.