title: LIN28 Zinc Knuckle Domain Is Required and Sufficient to Induce let-7 Oligouridylation.
abstract: LIN28 is an RNA binding protein that plays crucial roles in pluripotency, glucose metabolism, tissue regeneration, and tumorigenesis. LIN28 binds to the let-7 primary and precursor microRNAs through bipartite recognition and induces degradation of let-7 precursors (pre-let-7) by promoting oligouridylation by terminal uridylyltransferases (TUTases). Here, we report that the zinc knuckle domain (ZKD) of mouse LIN28 recruits TUT4 to initiate the oligouridylation of let-7 precursors. Our crystal structure of human LIN28 in complex with a fragment of pre-let-7f-1 determined to 2.0 Å resolution shows that the interaction between ZKD and RNA is constrained to a small cavity with a high druggability score. We demonstrate that the specific interaction between ZKD and pre-let-7 is necessary and sufficient to induce oligouridylation by recruiting the N-terminal fragment of TUT4 (NTUT4) and the formation of a stable ZKD:NTUT4:pre-let-7 ternary complex is crucial for the acquired processivity of TUT4.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Longfei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Yunsun
authors.initials: Y
authors.lastname: Nam
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Lee
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Kira
authors.initials: K
authors.lastname: Roth
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Casandra
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Ransey
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA. Electronic address: sliz@hkl.hms.harvard.edu.
authors.forename: Piotr
authors.initials: P
authors.lastname: Sliz
mesh_terms: D000818:Animals; D001483:Base Sequence; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D000072417:Protein Domains; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance; D014529:Uridine / Q000378:metabolism*
chemical_list: C488352:Lin-28 protein, mouse; C000715187:Lin28A protein, human; D035683:MicroRNAs; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C542687:mirnlet7 microRNA, mouse; D043244:Ribonuclease III; D014529:Uridine
keywords: LIN28; LIN28A; RNA binding protein; RNA degradation; TUT4; TUTase; X-ray structure; Zcchc11; let-7; oligouridylation