PDF(Pubmed)
Abstract：
Chromatin remodeling and N6-methyladenosine (m6A) modification are two critical layers in controlling gene expression and DNA damage signaling in most eukaryotic bioprocesses. Here, we report that poly(ADP-ribose) polymerase 1 (PARP1) controls the chromatin accessibility of METTL3 to regulate its transcription and subsequent m6A methylation of poly(A)+ RNA in response to DNA damage induced by radiation. The transcription factors nuclear factor I-C (NFIC) and TATA binding protein (TBP) are dependent on PARP1 to access the METTL3 promoter to activate METTL3 transcription. Upon irradiation or PARP1 inhibitor treatment, PARP1 disassociated from METTL3 promoter chromatin, which resulted in attenuated accessibility of NFIC and TBP and, consequently, suppressed METTL3 expression and RNA m6A methylation. Lysophosphatidic Acid Receptor 5 (LPAR5) mRNA was identified as a target of METTL3, and m6A methylation was located at A1881. The level of m6A methylation of LPAR5 significantly decreased, along with METTL3 depression, in cells after irradiation or PARP1 inhibition. Mutation of the LPAR5 A1881 locus in its 3\' UTR results in loss of m6A methylation and, consequently, decreased stability of LPAR5 mRNA. METTL3-targeted small-molecule inhibitors depress murine xenograft tumor growth and exhibit a synergistic effect with radiotherapy in vivo. These findings advance our comprehensive understanding of PARP-related biological roles, which may have implications for developing valuable therapeutic strategies for PARP1 inhibitors in oncology.
摘要：
在大多数真核生物过程中，染色质重塑和m6A修饰是控制基因表达和DNA损伤信号传导的两个关键层。这里,我们报道,PARP1控制METTL3的染色质可及性,以调节其转录和随后poly(A)+RNA的m6A甲基化,以响应辐射诱导的DNA损伤。转录因子NFIC和TBP依赖于PARP1进入METTL3启动子以激活METTL3转录。照射或PARP1抑制剂治疗后，PARP1与METTL3启动子染色质分离，这导致NFIC和TBP的可及性减弱，因此抑制了METTL3表达和RNAm6A甲基化。LPAR5mRNA被鉴定为METTL3的靶标，m6A甲基化位于A1881。照射后细胞中LPAR5的m6A甲基化水平随着METTL3抑制或PARP1抑制而显著降低。LPAR5A1881基因座在其3'UTR中的突变导致m6A甲基化的丧失,并因此降低LPAR5mRNA的稳定性。METTL3靶向的小分子抑制剂抑制小鼠异种移植肿瘤生长，并表现出与体内放疗的协同作用。这些发现促进了我们对PARP相关生物学作用的全面理解，这可能对在肿瘤学中开发PARP1抑制剂的有价值的治疗策略有影响。
