title: Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model.
abstract: CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase (DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein-RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecular dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: deLorimier
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Coonrod
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Copperman
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Taber
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Reister
authors.affiliation: Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Kush
authors.initials: K
authors.lastname: Sharma
authors.affiliation: Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Todd
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
authors.forename: Marina G
authors.initials: MG
authors.lastname: Guenza
authors.affiliation: Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA aberglund@molbio.uoregon.edu.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Berglund
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D020137:Base Pair Mismatch; D004195:Disease Models, Animal; D006367:HeLa Cells; D006801:Humans; D008745:Methylation; D009223:Myotonic Dystrophy / Q000235:genetics*; D009690:Nucleic Acid Conformation; D011560:Pseudouridine / Q000737:chemistry; D012313:RNA / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D014867:Water / Q000737:chemistry; D015027:Zebrafish / Q000235:genetics
chemical_list: D016601:RNA-Binding Proteins; D014867:Water; D011560:Pseudouridine; D012313:RNA