title: Structural insights into the targeting of mRNA GU-rich elements by the three RRMs of CELF1.
abstract: The CUG-BP, Elav-like family (CELF) of RNA-binding proteins control gene expression at a number of different levels by regulating pre-mRNA splicing, deadenylation and mRNA stability. We present structural insights into the binding selectivity of CELF member 1 (CELF1) for GU-rich mRNA target sequences of the general form 5'-UGUNxUGUNyUGU and identify a high affinity interaction (Kd ∼ 100 nM for x = 2 and y = 4) with simultaneous binding of all three RNA recognition motifs within a single 15-nt binding element. RNA substrates spin-labelled at either the 3' or 5' terminus result in differential nuclear magnetic resonance paramagnetic relaxation enhancement effects, which are consistent with a non-sequential 2-1-3 arrangement of the three RNA recognition motifs on UGU sites in a 5' to 3' orientation along the RNA target. We further demonstrate that CELF1 binds to dispersed single-stranded UGU sites at the base of an RNA hairpin providing a structural rationale for recognition of CUG expansion repeats and splice site junctions in the regulation of alternative splicing.
authors.affiliation: School of Chemistry, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Edwards
authors.forename: Jed
authors.initials: J
authors.lastname: Long
authors.forename: Cornelia H
authors.initials: CH
authors.lastname: de Moor
authors.forename: Jonas
authors.initials: J
authors.lastname: Emsley
authors.forename: Mark S
authors.initials: MS
authors.lastname: Searle
mesh_terms: D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy; D006147:Guanine / Q000032:analysis; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D014529:Uridine / Q000032:analysis; D029867:Xenopus Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: C568810:CELF1 protein, Xenopus; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029867:Xenopus Proteins; D006147:Guanine; D014529:Uridine