title: Characterization of the RNA recognition mode of hnRNP G extends its role in SMN2 splicing regulation.
abstract: Regulation of SMN2 exon 7 splicing is crucial for the production of active SMN protein and the survival of Spinal Muscular Atrophy (SMA) patients. One of the most efficient activators of exon 7 inclusion is hnRNP G, which is recruited to the exon by Tra2-β1. We report that in addition to the C-terminal region of hnRNP G, the RNA Recognition Motif (RRM) and the middle part of the protein containing the Arg-Gly-Gly (RGG) box are important for this function. To better understand the mode of action of hnRNP G in this context we determined the structure of its RRM bound to an SMN2 derived RNA. The RRM interacts with a 5'-AAN-3' motif and specifically recognizes the two consecutive adenines. By testing the effect of mutations in hnRNP G RRM and in its putative binding sites on the splicing of SMN2 exon 7, we show that it specifically binds to exon 7. This interaction is required for hnRNP G splicing activity and we propose its recruitment to a polyA tract located upstream of the Tra2-β1 binding site. Finally, our data suggest that hnRNP G plays a major role in the recruitment of the Tra2-β1/hnRNP G/SRSF9 trimeric complex to SMN2 exon 7.
authors.affiliation: Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Moursy
authors.affiliation: Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland aclery@mol.biol.ethz.ch.
authors.forename: Frédéric H-T
authors.initials: FH
authors.lastname: Allain
authors.affiliation: Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland aclery@mol.biol.ethz.ch.
authors.forename: Antoine
authors.initials: A
authors.lastname: Cléry
mesh_terms: D000225:Adenine / Q000737:chemistry; D020816:Amino Acid Motifs; D001665:Binding Sites; D005091:Exons; D057809:HEK293 Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000378:metabolism; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics* / Q000378:metabolism
chemical_list: D034441:Heterogeneous-Nuclear Ribonucleoproteins; C510272:RBMX protein, human; D016601:RNA-Binding Proteins; D055540:Survival of Motor Neuron 2 Protein; D012313:RNA; D000225:Adenine