PDF(Pubmed)
Abstract：
The epitranscriptome includes a diversity of RNA modifications that influence gene expression. N3-methylcytidine (m3C) mainly occurs in the anticodon loop (position C32) of certain tRNAs yet its role is poorly understood. Here, using HAC-Seq, we report comprehensive METTL2A/2B-, METTL6-, and METTL2A/2B/6-dependent m3C profiles in human cells. METTL2A/2B modifies tRNA-arginine and tRNA-threonine members, whereas METTL6 modifies the tRNA-serine family. However, decreased m3C32 on tRNA-Ser-GCT isodecoders is only observed with combined METTL2A/2B/6 deletion. Ribo-Seq reveals altered translation of genes related to cell cycle and DNA repair pathways in METTL2A/2B/6-deficient cells, and these mRNAs are enriched in AGU codons that require tRNA-Ser-GCT for translation. These results, supported by reporter assays, help explain the observed altered cell cycle, slowed proliferation, and increased cisplatin sensitivity phenotypes of METTL2A/2B/6-deficient cells. Thus, we define METTL2A/2B/6-dependent methylomes and uncover a particular requirement of m3C32 tRNA modification for serine codon-biased mRNA translation of cell cycle, and DNA repair genes.
摘要：
表位转录组包括影响基因表达的多种RNA修饰。N3-甲基胞苷（m3C）主要存在于某些tRNA的反密码子环（位置C32）中，但对其作用知之甚少。这里,使用HAC-Seq，我们报告了全面的METTL2A/2B-，METTL6-,和METTL2A/2B/6依赖性m3C在人细胞中的分布。METTL2A/2B修饰tRNA-精氨酸和tRNA-苏氨酸成员，而METTL6修饰了tRNA-丝氨酸家族。然而,tRNA-Ser-GCT等解码器上的m3C32减少仅在组合METTL2A/2B/6缺失时观察到。Ribo-Seq揭示了METTL2A/2B/6缺陷细胞中与细胞周期和DNA修复途径相关的基因翻译的改变，并且这些mRNA富集在需要tRNA-Ser-GCT进行翻译的AGU密码子中。这些结果,由报告检测支持，帮助解释观察到的细胞周期改变，减缓增殖，METTL2A/2B/6缺陷细胞的顺铂敏感性表型增加。因此，我们定义了METTL2A/2B/6依赖的甲基化组，并揭示了m3C32tRNA修饰对于细胞周期的丝氨酸密码子偏向性mRNA翻译的特殊要求，和DNA修复基因.
