title: Novel domains in the hnRNP G/RBMX protein with distinct roles in RNA binding and targeting nascent transcripts.
abstract: The heterogenous nuclear ribonucleoprotein G (hnRNP G) controls the alternative splicing of several pre-mRNas. While hnRNP G displays an amino terminal RNA recognition motif (RRM), we find that this motif is paradoxically not implicated in the recruitment of hnRNP G to nascent transcripts in amphibian oocytes. In fact, a deletion analysis revealed that targeting of hnRNP G to active transcription units depends on another domain, centrally positioned, and consisting of residues 186-236. We show that this domain acts autonomously and thus is named NTD for nascent transcripts targeting domain. Furthermore, using an RNA probe previously characterized in vitro as an RNA that interacts specifically with hnRNP G, we demonstrate a new auxiliary RNA binding domain (RBD). It corresponds to a short region of 58 residues positioned at the carboxyl terminal end of the protein, which recognizes an RNA motif predicted to adopt an hairpin structure. The fact that the NTD acts independently from both the RRM and the RBD strongly suggests that the initial recruitment of hnRNP G to nascent pre-mRNAs is independent of its sequence-specific RNA binding properties. Together, these findings highlight the modular organization of hnRNP G and offer new insights into its multifunctional roles.
authors.affiliation: Institut Jacques Monod, CNRS and Université Paris-Diderot, Paris, France.
authors.forename: Rasha
authors.initials: R
authors.lastname: Kanhoush
authors.forename: Brent
authors.initials: B
authors.lastname: Beenders
authors.forename: Caroline
authors.initials: C
authors.lastname: Perrin
authors.forename: Jacques
authors.initials: J
authors.lastname: Moreau
authors.forename: Michel
authors.initials: M
authors.lastname: Bellini
authors.forename: May
authors.initials: M
authors.lastname: Penrad-Mobayed
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D059372:Nucleotide Motifs; D009865:Oocytes / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D015347:RNA Probes / Q000378:metabolism; D016415:Sequence Alignment; D014981:Xenopus / Q000378:metabolism
chemical_list: D034441:Heterogeneous-Nuclear Ribonucleoproteins; C510272:RBMX protein, human; D012322:RNA Precursors; D015347:RNA Probes; D012313:RNA; D012319:RNA Polymerase II