Expression, localization and tau exon 10 splicing activity of the brain RNA-binding protein TNRC4.
Elucidating the mechanisms of alternative splicing in the brain is a prerequisite to the understanding of the pathogenesis of major neurological diseases linked to impairment of pre-mRNA alternative splicing. The gene trinucleotide repeat-containing 4 (TNRC4) is predicted to encode a member of the CELF (CUG-BP- and ETR-3-like factors) family of RNA-binding proteins containing a 15-18-residue polyglutamine sequence. The TNRC4 transcript is selectively expressed in the brain. Using an anti-peptide antibody against the predicted sequence, we establish the presence of TNRC4 as a approximately 50 kDa protein in the brain. Full-length TNRC4 displays nuclear and cytoplasmic localizations in transfected cells, whereas a C-terminally truncated mutant is essentially confined to the cytoplasm. TNRC4 is not recruited into inclusions formed by polyglutamine-expanded ataxin-1 or huntingtin. TNRC4 activates tau exon 10 (E10) inclusion at high efficiency in transfected cells. TNRC4 contains two consecutive N-terminal RNA recognition motifs (RRMs) separated from the C-terminal RRM. Deletion and point mutant analysis show that the activity of TNRC4 on tau E10 splicing is mainly mediated by the RNA-binding activity of the second RRM and involves an intronic element of the tau pre-mRNA. The polyglutamine sequence has no effect on the activity of TNRC4 on tau E10 splicing. This study represents the first characterization of TNRC4 and provides further insight into the mechanisms of brain-specific alternative splicing and their possible pathological implications.
Chapple
J Paul
JP
MRC Centre for Neurodegeneration Research, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
Anthony
Karen
K
Martin
Teresa Rodriguez
TR
Dev
Arvind
A
Cooper
Thomas A
TA
Gallo
Jean-Marc
JM
D017398:Alternative Splicing; D000818:Animals; D000067696:Ataxin-1; D000067528:Ataxins; D015153:Blotting, Western; D001921:Brain; D000067878:CELF Proteins; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005091:Exons / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D006801:Humans; D000071058:Huntingtin Protein; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D010455:Peptides / Q000235:genetics; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution; D014162:Transfection; D016875:tau Proteins / Q000235:genetics* / Q000378:metabolism
C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D000067528:Ataxins; C000593750:Atxn1 protein, mouse; D000067878:CELF Proteins; C422242:CELF3 protein, human; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010455:Peptides; D020033:Protein Isoforms; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D016875:tau Proteins; C097188:polyglutamine