title: hnRNP U protein is required for normal pre-mRNA splicing and postnatal heart development and function.
abstract: We report that mice lacking the heterogeneous nuclear ribonucleoprotein U (hnRNP U) in the heart develop lethal dilated cardiomyopathy and display numerous defects in cardiac pre-mRNA splicing. Mutant hearts have disorganized cardiomyocytes, impaired contractility, and abnormal excitation-contraction coupling activities. RNA-seq analyses of Hnrnpu mutant hearts revealed extensive defects in alternative splicing of pre-mRNAs encoding proteins known to be critical for normal heart development and function, including Titin and calcium/calmodulin-dependent protein kinase II delta (Camk2d). Loss of hnRNP U expression in cardiomyocytes also leads to aberrant splicing of the pre-mRNA encoding the excitation-contraction coupling component Junctin. We found that the protein product of an alternatively spliced Junctin isoform is N-glycosylated at a specific asparagine site that is required for interactions with specific protein partners. Our findings provide conclusive evidence for the essential role of hnRNP U in heart development and function and in the regulation of alternative splicing.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032;
authors.forename: Junqiang
authors.initials: J
authors.lastname: Ye
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390; Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Beetz
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032;
authors.forename: Sean
authors.initials: S
authors.lastname: O'Keeffe
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032;
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Tapia
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032;
authors.forename: Lindsey
authors.initials: L
authors.lastname: Macpherson
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032;
authors.forename: Weisheng V
authors.initials: WV
authors.lastname: Chen
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390;
authors.forename: Rhonda
authors.initials: R
authors.lastname: Bassel-Duby
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390;
authors.forename: Eric N
authors.initials: EN
authors.lastname: Olson
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032; tm2472@columbia.edu.
authors.forename: Tom
authors.initials: T
authors.lastname: Maniatis
mesh_terms: D017398:Alternative Splicing / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D006031:Glycosylation; D006321:Heart / Q000254:growth & development* / Q000502:physiology*; D034722:Heterogeneous-Nuclear Ribonucleoprotein U / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D009154:Mutation; D012322:RNA Precursors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012518:Sarcomeres / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D008565:Membrane Proteins; D009124:Muscle Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; C498841:Asph protein, mouse; D006899:Mixed Function Oxygenases; D002118:Calcium
keywords: N-glycosylation; RNA-seq; alternative splicing; dilated cardiomyopathy; heart development