Hypoxia as a crucial pathogenesis factor usually results in huge harmful effects on cardiac injury and dysfunction. Our previous study has uncovered the global transcriptome and translatome profiles of cardiomyocytes in vitro and in vivo to response to hypoxia by RNA sequencing and ribosome profiling sequencing. We observe a series of differential expressed genes between transcription and translation, which may be attributed to the hypoxia-specific binding affinity of nuclear cap-binding subunit 3 (NCBP3) at 5' untranslation region of target genes. Although we observe that NCBP3 can facilitate translational process in myocardium under hypoxia stress, the underlying molecular mechanism of NCBP3 for gene translation modulation remains unclear. In this study, we performed NCBP3 immunoprecipitation for mass spectrum and found that METTL3 and eIF4A2 particularly interacted with NCBP3 in hypoxic rat H9C2 cardiomyocytes. Furthermore, we observed that METTL3-mediated N6-methyladenosine (m6A) methylation was elevated in hypoxia, but compromised by NCBP3 or METTL3 knockdown. Finally, we also demonstrated that NCBP3/METTL3/eIF4A2 regulatory axis plays a specific role in cardiomyocytes undergoing hypoxic stress. Taken together, we unmasked NCBP3, a novel hypoxia-specific response protein functions as a scaffold to coordinate METTL3 and eIF4A2 for enhancing gene translation by m6A RNA methylation in cardiomyocytes upon hypoxic stress.

中文翻译：

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NCBP3对METTL3介导的m6A RNA甲基化增强缺氧心肌细胞翻译过程的影响

缺氧作为一个重要的发病因素通常会对心脏损伤和功能障碍产生巨大的有害影响。我们之前的研究通过 RNA 测序和核糖体谱测序揭示了心肌细胞在体外和体内对缺氧反应的全球转录组和翻译组谱。我们观察到一系列转录和翻译之间的差异表达基因，这可能归因于靶基因5'非翻译区核帽结合亚基3（NCBP3）的缺氧特异性结合亲和力。虽然我们观察到 NCBP3 可以促进缺氧应激下心肌的翻译过程，但 NCBP3 基因翻译调节的潜在分子机制仍不清楚。在这项研究中，我们对质谱进行了 NCBP3 免疫沉淀，发现 METTL3 和 eIF4A2 特别与缺氧大鼠 H9C2 心肌细胞中的 NCBP3 相互作用。此外，我们观察到 METTL3 介导的 N6-甲基腺苷 (m6A) 甲基化在缺氧时升高，但受到 NCBP3 或 METTL3 敲低的影响。最后，我们还证明了 NCBP3/METTL3/eIF4A2 调节轴在经历缺氧应激的心肌细胞中起特定作用。总之，我们揭示了 NCBP3，这是一种新型的缺氧特异性反应蛋白，可作为支架协调 METTL3 和 eIF4A2，通过 m6A RNA 甲基化在缺氧应激时增强心肌细胞中的基因翻译。但受到 NCBP3 或 METTL3 敲低的影响。最后，我们还证明了 NCBP3/METTL3/eIF4A2 调节轴在经历缺氧应激的心肌细胞中起特定作用。总之，我们揭示了 NCBP3，这是一种新型的缺氧特异性反应蛋白，可作为支架协调 METTL3 和 eIF4A2，通过 m6A RNA 甲基化在缺氧应激时增强心肌细胞中的基因翻译。但受到 NCBP3 或 METTL3 敲低的影响。最后，我们还证明了 NCBP3/METTL3/eIF4A2 调节轴在经历缺氧应激的心肌细胞中起特定作用。总之，我们揭示了 NCBP3，这是一种新型的缺氧特异性反应蛋白，可作为支架协调 METTL3 和 eIF4A2，通过 m6A RNA 甲基化在缺氧应激时增强心肌细胞中的基因翻译。