title: Alkbh8 Regulates Selenocysteine-Protein Expression to Protect against Reactive Oxygen Species Damage.
abstract: Environmental and metabolic sources of reactive oxygen species (ROS) can damage DNA, proteins and lipids to promote disease. Regulation of gene expression can prevent this damage and can include increased transcription, translation and post translational modification. Cellular responses to ROS play important roles in disease prevention, with deficiencies linked to cancer, neurodegeneration and ageing. Here we detail basal and damage-induced translational regulation of a group of oxidative-stress response enzymes by the tRNA methyltransferase Alkbh8. Using a new gene targeted knockout mouse cell system, we show that Alkbh8-/- embryonic fibroblasts (MEFs) display elevated ROS levels, increased DNA and lipid damage and hallmarks of cellular stress. We demonstrate that Alkbh8 is induced in response to ROS and is required for the efficient expression of selenocysteine-containing ROS detoxification enzymes belonging to the glutathione peroxidase (Gpx1, Gpx3, Gpx6 and likely Gpx4) and thioredoxin reductase (TrxR1) families. We also show that, in response to oxidative stress, the tRNA modification 5-methoxycarbonylmethyl-2'-O-methyluridine (mcm5Um) increases in normal MEFs to drive the expression of ROS detoxification enzymes, with this damage-induced reprogramming of tRNA and stop-codon recoding corrupted in Alkbh8-/- MEFS. These studies define Alkbh8 and tRNA modifications as central regulators of cellular oxidative stress responses in mammalian systems. In addition they highlight a new animal model for use in environmental and cancer studies and link translational regulation to the prevention of DNA and lipid damage.
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America; RNA Institute and Cancer Research Center, University at Albany, State University of New York, Albany, New York 12222, United States of America.
authors.forename: Lauren
authors.initials: L
authors.lastname: Endres
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Begley
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America.
authors.forename: Ryan
authors.initials: R
authors.lastname: Clark
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America.
authors.forename: Chen
authors.initials: C
authors.lastname: Gu
authors.affiliation: Institute of Organic Chemistry, Lodz University of Technology, Lodz, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Dziergowska
authors.affiliation: Institute of Organic Chemistry, Lodz University of Technology, Lodz, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Małkiewicz
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America.
authors.forename: J Andres
authors.initials: JA
authors.lastname: Melendez
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America; Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore; Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States of America.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Dedon
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States of America; RNA Institute and Cancer Research Center, University at Albany, State University of New York, Albany, New York 12222, United States of America.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Begley
mesh_terms: D000071503:AlkB Homolog 8, tRNA Methyltransferase; D000818:Animals; D004249:DNA Damage / Q000235:genetics*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D005979:Glutathione Peroxidase / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics*; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017279:Selenocysteine / Q000235:genetics*; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics; D014529:Uridine / Q000031:analogs & derivatives / Q000494:pharmacology; D012359:tRNA Methyltransferases / Q000235:genetics*
chemical_list: D017382:Reactive Oxygen Species; D017279:Selenocysteine; C030689:5-methoxycarbonylmethyluridine; D012343:RNA, Transfer; D005979:Glutathione Peroxidase; C548496:ALKBH8 protein, mouse; D000071503:AlkB Homolog 8, tRNA Methyltransferase; D013880:Thioredoxin-Disulfide Reductase; D012359:tRNA Methyltransferases; D014529:Uridine