title: Structural basis of pre-let-7 miRNA recognition by the zinc knuckles of pluripotency factor Lin28.
abstract: Lin28 inhibits the biogenesis of let-7 miRNAs through a direct interaction with the terminal loop of pre-let-7. This interaction requires the zinc-knuckle domains of Lin28. We show that the zinc knuckle domains of Lin28 are sufficient to provide binding selectivity for pre-let-7 miRNAs and present the NMR structure of human Lin28 zinc knuckles bound to the short sequence 5'-AGGAGAU-3'. The structure reveals that each zinc knuckle recognizes an AG dinucleotide separated by a single nucleotide spacer. This defines a new 5'-NGNNG-3' consensus motif that explains how Lin28 selectively recognizes pre-let-7 family members. Binding assays in cell lysates and functional assays in cultured cells demonstrate that the interactions observed in the solution structure also occur between the full-length protein and members of the pre-let-7 family. The consensus sequence explains several seemingly disparate previously published observations on the binding properties of Lin28.
authors.affiliation: Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
authors.forename: Fionna E
authors.initials: FE
authors.lastname: Loughlin
authors.forename: Luca F R
authors.initials: LF
authors.lastname: Gebert
authors.forename: Harry
authors.initials: H
authors.lastname: Towbin
authors.forename: Andreas
authors.initials: A
authors.lastname: Brunschweiger
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hall
authors.forename: Frédéric H-T
authors.initials: FH
authors.lastname: Allain
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002151:Calorimetry; D045744:Cell Line, Tumor; D006367:HeLa Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D035683:MicroRNAs / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D059372:Nucleotide Motifs / Q000235:genetics; D009843:Oligoribonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
chemical_list: C000715187:Lin28A protein, human; D035683:MicroRNAs; D009843:Oligoribonucleotides; D016601:RNA-Binding Proteins; C487931:mirnlet7 microRNA, human