title: AlkB homolog 3-mediated tRNA demethylation promotes protein synthesis in cancer cells.
abstract: The mammalian AlkB homolog (ALKBH) family of proteins possess a 2-oxoglutarate- and Fe(II)-dependent oxygenase domain. A similar domain in the Escherichia coli AlkB protein catalyzes the oxidative demethylation of 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) in both DNA and RNA. AlkB homolog 3 (ALKBH3) was also shown to demethylate 1-meA and 3-meC (induced in single-stranded DNA and RNA by a methylating agent) to reverse the methylation damage and retain the integrity of the DNA/RNA. We previously reported the high expression of ALKBH3 in clinical tumor specimens and its involvement in tumor progression. In this study, we found that ALKBH3 effectively demethylated 1-meA and 3-meC within endogenously methylated RNA. Moreover, using highly purified recombinant ALKBH3, we identified N6-methyladenine (N6-meA) in mammalian transfer RNA (tRNA) as a novel ALKBH3 substrate. An in vitro translation assay showed that ALKBH3-demethylated tRNA significantly enhanced protein translation efficiency. In addition, ALKBH3 knockdown in human cancer cells impaired cellular proliferation and suppressed the nascent protein synthesis that is usually accompanied by accumulation of the methylated RNAs. Thus, our data highlight a novel role for ALKBH3 in tumor progression via RNA demethylation and subsequent protein synthesis promotion.
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ueda
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Ikumi
authors.initials: I
authors.lastname: Ooshio
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Fusamae
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Kitae
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Kawaguchi
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Jingushi
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hase
authors.affiliation: Laboratory of Applied Environmental Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Harada
authors.affiliation: Laboratory of Applied Environmental Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Hirata
authors.affiliation: Laboratory of Molecular and Cellular Physiology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan.
authors.forename: Kazutake
authors.initials: K
authors.lastname: Tsujikawa
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000378:metabolism; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase / Q000378:metabolism*; D000071502:AlkB Homolog 5, RNA Demethylase / Q000378:metabolism; D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D003596:Cytosine / Q000031:analogs & derivatives / Q000378:metabolism; D000073398:Demethylation; D055785:Gene Knockdown Techniques; D006801:Humans; D008745:Methylation; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; C036386:3-methylcytosine; C008407:1-methyladenine; D003596:Cytosine; D012343:RNA, Transfer; C486439:ALKBH3 protein, human; C559920:ALKBH5 protein, human; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase; D000071502:AlkB Homolog 5, RNA Demethylase; D000225:Adenine