Jia Guifang, Yang Cai-Guang, Yang Shangdong, Jian Xing, Yi Chengqi, Zhou Zhiqiang, He Chuan
Department of Chemistry, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
FEBS Lett. 2008 Oct 15;582(23-24):3313-9. doi: 10.1016/j.febslet.2008.08.019. Epub 2008 Sep 5.
The human obesity susceptibility gene, FTO, encodes a protein that is homologous to the DNA repair AlkB protein. The AlkB family proteins utilize iron(II), alpha-ketoglutarate (alpha-KG) and dioxygen to perform oxidative repair of alkylated nucleobases in DNA and RNA. We demonstrate here the oxidative demethylation of 3-methylthymine (3-meT) in single-stranded DNA (ssDNA) and 3-methyluracil (3-meU) in single-stranded RNA (ssRNA) by recombinant human FTO protein in vitro. Both human and mouse FTO proteins preferentially repair 3-meT in ssDNA over other base lesions tested. They showed negligible activities against 3-meT in double-stranded DNA (dsDNA). In addition, these two proteins can catalyze the demethylation of 3-meU in ssRNA with a slightly higher efficiency over that of 3-meT in ssDNA, suggesting that methylated RNAs are the preferred substrates for FTO.
人类肥胖易感性基因FTO编码一种与DNA修复AlkB蛋白同源的蛋白质。AlkB家族蛋白利用亚铁离子、α-酮戊二酸（α-KG）和双加氧来对DNA和RNA中的烷基化核碱基进行氧化修复。我们在此证明，重组人FTO蛋白在体外可对单链DNA（ssDNA）中的3-甲基胸腺嘧啶（3-meT）和单链RNA（ssRNA）中的3-甲基尿嘧啶（3-meU）进行氧化去甲基化。与其他测试的碱基损伤相比，人和小鼠的FTO蛋白都优先修复ssDNA中的3-meT。它们对双链DNA（dsDNA）中的3-meT活性可忽略不计。此外，这两种蛋白可催化ssRNA中3-meU的去甲基化，效率略高于ssDNA中的3-meT，这表明甲基化RNA是FTO的首选底物。
