N⁶-methyladenosine (m⁶A), a ubiquitous internal modification of eukaryotic mRNAs, plays a vital role in almost every aspect of mRNA metabolism. However, there is little evidence documenting the role of m⁶A in regulating alternative polyadenylation (APA) in plants. APA is controlled by a large protein-RNA complex with many components, including CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30 (CPSF30). In Arabidopsis, CPSF30 has two isoforms and the longer isoform (CPSF30-L) contains a YT512-B Homology (YTH) domain, which is unique to plants. In this study, we showed that CPSF30-L YTH domain binds to m⁶A in vitro. In the cpsf30-2 mutant, the transcripts of many genes including several important nitrate signaling-related genes had shifts in polyadenylation sites that were correlated with m⁶A peaks, indicating that these gene transcripts carrying m⁶A tend to be regulated by APA. Wild-type CPSF30-L could rescue the defects in APA and nitrate metabolism in cpsf30-2, but m⁶A-binding-defective mutants of CPSF30-L could not. Taken together, our results demonstrated that m⁶A modification regulates APA in Arabidopsis and revealed that the m⁶A reader CPSF30-L affects nitrate signaling by controlling APA, shedding new light on the roles of the m⁶A modification during RNA 3′-end processing in nitrate metabolism.

N ⁶ -methyladenosine (m ⁶ A) 是一种无处不在的真核 mRNA 内部修饰，几乎在 mRNA 代谢的每个方面都起着至关重要的作用。然而，几乎没有证据证明 m ⁶ A 在调节植物中的替代多聚腺苷酸化 (APA) 中的作用。APA 由具有许多成分的大型蛋白质-RNA 复合物控制，包括切割和聚腺苷酸化特异性因子 30 (CPSF30)。在拟南芥中，CPSF30 具有两种同种型，较长的同种型 (CPSF30-L) 包含植物独有的 YT512-B 同源 (YTH) 域。在这项研究中，我们表明 CPSF30-L YTH 结构域在体外与 m ⁶ A结合。在cpsf30-2在突变体中，包括几个重要的硝酸盐信号相关基因在内的许多基因的转录物在与 m ⁶ A 峰相关的多腺苷酸化位点发生了变化，表明这些携带 m ⁶ A 的基因转录物倾向于受 APA 调节。野生型CPSF30-L可以修复cpsf30-2中APA和硝酸盐代谢的缺陷，但CPSF30-L的m ⁶ A结合缺陷突变体不能。总之，我们的结果表明 m ⁶ A 修饰调节拟南芥中的APA， 并揭示了 m ⁶ A 阅读器 CPSF30-L 通过控制 APA 影响硝酸盐信号传导，为 m ⁶的作用提供了新的线索硝酸盐代谢中RNA 3'-末端加工过程中的修饰。