Editing modifies the GABAA receptor subunit α3

Adenosine to inosine (A-to-I) pre-mRNA editing by the ADAR enzyme family has the potential to increase the variety of the proteome. This editing by adenosine deamination is essential in mammals for a functional brain. To detect novel substrates for A-to-I editing we have used an experimental method to find selectively edited sites and combined it with bioinformatic techniques that find stem–loop structures suitable for editing. We present here the first verified editing candidate detected by this screening procedure. We show that Gabra-3, which codes for the α3 subunit of the GABAA receptor, is a substrate for editing by both ADAR1 and ADAR2. Editing of the Gabra-3 mRNA recodes an isoleucine to a methionine. The extent of editing is low at birth but increases with age, reaching close to 100% in the adult brain. We therefore propose that editing of the Gabra-3 mRNA is important for normal brain development.

[1]  Johan Ohlson,et al.  A method to find tissue-specific novel sites of selective adenosine deamination , 2005, Nucleic acids research.

[2]  A. Meyer,et al.  Recent Advances in the (Molecular) Phylogeny of Vertebrates , 2003 .

[3]  D. Feldmeyer,et al.  Point mutation in an AMPA receptor gene rescues lethality in mice deficient in the RNA-editing enzyme ADAR2 , 2000, Nature.

[4]  M. Weiss,et al.  Stress-induced Apoptosis Associated with Null Mutation of ADAR1 RNA Editing Deaminase Gene* , 2004, Journal of Biological Chemistry.

[5]  S. Moss,et al.  Constructing inhibitory synapses , 2001, Nature Reviews Neuroscience.

[6]  R. Emeson,et al.  Regulation of serotonin-2C receptor G-protein coupling by RNA editing , 1997, Nature.

[7]  P. Seeburg,et al.  Regulation of ion channel/neurotransmitter receptor function by RNA editing , 2003, Current Opinion in Neurobiology.

[8]  Elizabeth M. Smigielski,et al.  dbSNP: the NCBI database of genetic variation , 2001, Nucleic Acids Res..

[9]  P. Seeburg,et al.  RNA editing of AMPA receptor subunit GluR-B: A base-paired intron-exon structure determines position and efficiency , 1993, Cell.

[10]  Brenda L Bass,et al.  RNA editing by adenosine deaminases that act on RNA. , 2002, Annual review of biochemistry.

[11]  T. N. Bhat,et al.  The Protein Data Bank , 2000, Nucleic Acids Res..

[12]  P. Seeburg,et al.  Liver Disintegration in the Mouse Embryo Caused by Deficiency in the RNA-editing Enzyme ADAR1* , 2004, Journal of Biological Chemistry.

[13]  B. Sakmann,et al.  Divalent ion permeability of AMPA receptor channels is dominated by the edited form of a single subunit , 1992, Neuron.

[14]  M. Ohman,et al.  Coordination of editing and splicing of glutamate receptor pre-mRNA. , 2003, RNA.

[15]  T. Blundell,et al.  Comparative protein modelling by satisfaction of spatial restraints. , 1993, Journal of molecular biology.

[16]  W Wisden,et al.  The distribution of thirteen GABAA receptor subunit mRNAs in the rat brain. III. Embryonic and postnatal development , 1992, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[17]  Dirk Feldmeyer,et al.  Early-Onset Epilepsy and Postnatal Lethality Associated with an Editing-Deficient GluR-B Allele in Mice , 1995, Science.

[18]  Terrence S. Furey,et al.  The UCSC Genome Browser Database: update 2006 , 2005, Nucleic Acids Res..

[19]  Y. Ben-Ari.  Excitatory actions of gaba during development: the nature of the nurture , 2002, Nature Reviews Neuroscience.

[20]  R. Dingledine,et al.  Identification of a site in glutamate receptor subunits that controls calcium permeability , 1991, Science.

[21]  J. Fisher.  A mutation in the GABAA receptor α1 subunit linked to human epilepsy affects channel gating properties , 2004, Neuropharmacology.

[22]  M. Carmo-Fonseca,et al.  Dynamic association of RNA-editing enzymes with the nucleolus , 2003, Journal of Cell Science.

[23]  M. Kiefmann,et al.  Retroposed Elements as Archives for the Evolutionary History of Placental Mammals , 2006, PLoS biology.

[24]  Alexander Rich,et al.  Widespread A-to-I RNA Editing of Alu-Containing mRNAs in the Human Transcriptome , 2004, PLoS biology.

[25]  K. Kaila,et al.  Developmental up‐regulation of KCC2 in the absence of GABAergic and glutamatergic transmission , 2003, The European journal of neuroscience.

[26]  Richard Wooster,et al.  A survey of RNA editing in human brain. , 2004, Genome research.

[27]  Zipora Y. Fligelman,et al.  Systematic identification of abundant A-to-I editing sites in the human transcriptome , 2004, Nature Biotechnology.

[28]  D. Swandulla,et al.  Hyperpolarizing Inhibition Develops without Trophic support by GABA in Cultured Rat Midbrain Neurons , 2003, The Journal of physiology.

[29]  W. Chow,et al.  Q/R RNA editing of the AMPA receptor subunit 2 (GRIA2) transcript evolves no later than the appearance of cartilaginous fishes , 2001, FEBS letters.

[30]  A. Källman,et al.  ADAR2 A-->I editing: site selectivity and editing efficiency are separate events. , 2003, Nucleic acids research.

[31]  S. Sato,et al.  Substrate recognition by ADAR1 and ADAR2. , 2001, RNA.

[32]  Amos Bairoch,et al.  Swiss-Prot: Juggling between evolution and stability , 2004, Briefings Bioinform..

[33]  M. Poo,et al.  GABA Itself Promotes the Developmental Switch of Neuronal GABAergic Responses from Excitation to Inhibition , 2001, Cell.

[34]  Joshua J C Rosenthal,et al.  Control of human potassium channel inactivation by editing of a small mRNA hairpin , 2004, Nature Structural &Molecular Biology.

[35]  H. Lüddens,et al.  Four Amino Acids in the α Subunits Determine the γ-Aminobutyric Acid Sensitivities of GABAA Receptor Subtypes* , 2004, Journal of Biological Chemistry.

[36]  Michael W Parker,et al.  Anxiety over GABA(A) receptor structure relieved by AChBP. , 2002, Trends in biochemical sciences.

[37]  David Haussler,et al.  Identification and Classification of Conserved RNA Secondary Structures in the Human Genome , 2006, PLoS Comput. Biol..