ALKBH1 is an RNA dioxygenase responsible for cytoplasmic and mitochondrial tRNA modifications.
ALKBH1 is an RNA dioxygenase responsible for cytoplasmic and mitochondrial tRNA modifications.
复制标题
DOI：
10.1093/nar/gkx354
复制
发表时间：
2017-07-07
影响因子：
14.9
通讯作者：
Suzuki T
中科院分区：
文献类型：
--
作者：
Kawarada L;Suzuki T;Ohira T;Hirata S;Miyauchi K;Suzuki T
ALKBH1是一种依赖于2-氧戊二酸和Fe2+的双加氧酶，负责多种细胞功能。在这里，我们发现ALKBH1参与了细胞质tRNALeu中反密码子第一位(34位)的5-羟甲基-2΄-O-甲基胞苷(Hm5Cm)和5-甲酰基-2΄-O-甲基胞苷(F5Cm)以及线粒体tRNAMet中相同位置的f5C的生物发生。由于线粒体tRNAMet的f5C34对于翻译哺乳动物线粒体中的一种非通用密码子AUA是必不可少的，ALKBH1基因敲除细胞表现出线粒体翻译的强烈减少和呼吸复合体活性的降低，表明ALKBH1介导的f5C34的形成是有效的线粒体功能所必需的。我们在体外重组了线粒体tRNAME上f5C34的形成，发现ALKBH1首先将m5C34羟化成hm5C34，然后氧化hm5C34形成f5C34。此外，我们还发现，在ALKBH1基因敲除细胞中，两个线粒体tRNAs中1-甲基腺苷(M1A)的频率增加，表明ALKBH1也对mt-tRNAs中的M1a具有去甲基化活性。根据这些结果，我们得出结论，核和线粒体ALKBH1在tRNA修饰中起着不同的作用。
ALKBH1 is a 2-oxoglutarate- and Fe2+-dependent dioxygenase responsible for multiple cellular functions. Here, we show that ALKBH1 is involved in biogenesis of 5-hydroxymethyl-2΄-O-methylcytidine (hm5Cm) and 5-formyl-2΄-O-methylcytidine (f5Cm) at the first position (position 34) of anticodon in cytoplasmic tRNALeu, as well as f5C at the same position in mitochondrial tRNAMet. Because f5C34 of mitochondrial tRNAMet is essential for translation of AUA, a non-universal codon in mammalian mitochondria, ALKBH1-knockout cells exhibited a strong reduction in mitochondrial translation and reduced respiratory complex activities, indicating that f5C34 formation mediated by ALKBH1 is required for efficient mitochondrial functions. We reconstituted formation of f5C34 on mitochondrial tRNAMetin vitro, and found that ALKBH1 first hydroxylated m5C34 to form hm5C34, and then oxidized hm5C34 to form f5C34. Moreover, we found that the frequency of 1-methyladenosine (m1A) in two mitochondrial tRNAs increased in ALKBH1-knockout cells, indicating that ALKBH1 also has demethylation activity toward m1A in mt-tRNAs. Based on these results, we conclude that nuclear and mitochondrial ALKBH1 play distinct roles in tRNA modification.