title: Evolutionarily conserved A-to-I editing increases protein stability of the alternative splicing factor Nova1.
abstract: The structural complexity of the vertebrate brain is mirrored by its unparalleled transcriptome complexity. In particular, two post-transcriptional processes, alternative splicing and RNA editing, greatly diversify brain transcriptomes. Here we report a close connection between these two processes: we show A-to-I RNA editing in Nova1, a key brain-specific regulator of alternative splicing. Nova1 editing levels increase during embryonic development in mouse and chicken brains and show significant variation across postnatal brain regions. Evolutionary conservation of both editing and editing-associated RNA secondary structure of the Nova1 mRNA for 300 million years attests to the functional importance of Nova1 editing. Using a combination of different assays in human HEK293T cell lines, we report a novel post-translational role for this RNA editing. Whereas functional assays showed no effect of RNA editing on the regulatory splicing activity of the encoded proteins, we found evidence that edited forms exhibit reduced proteasome targeting and increased protein half-life. In addition, we found evidence for similar regulation of protein half-life by an evolutionarily conserved alternative splicing event in Nova1. These results open new venues of research on the multi-level integration of gene expression by: (1) revealing the novel role of RNA editing in regulating protein stability, and (2) establishing protein stability as a new target of multifaceted regulation.
authors.affiliation: Departament de Genètica, Facultat de Biología, Universitat de Barcelona, Barcelona, Spain. mirimia@gmail.com
authors.forename: Manuel
authors.initials: M
authors.lastname: Irimia
authors.forename: Amanda
authors.initials: A
authors.lastname: Denuc
authors.forename: Jose L
authors.initials: JL
authors.lastname: Ferran
authors.forename: Barbara
authors.initials: B
authors.lastname: Pernaute
authors.forename: Luis
authors.initials: L
authors.lastname: Puelles
authors.forename: Scott W
authors.initials: SW
authors.lastname: Roy
authors.forename: Jordi
authors.initials: J
authors.lastname: Garcia-Fernàndez
authors.forename: Gemma
authors.initials: G
authors.lastname: Marfany
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D017398:Alternative Splicing; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002645:Chickens / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006207:Half-Life; D006801:Humans; D007288:Inosine / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D000090682:Neuro-Oncological Ventral Antigen; D009690:Nucleic Acid Conformation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D055550:Protein Stability; D059748:Proteolysis; D017393:RNA Editing; D022821:RNA Splice Sites; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D009419:Nerve Tissue Proteins; D000090682:Neuro-Oncological Ventral Antigen; C000608219:Nova1 protein, mouse; D022821:RNA Splice Sites; D016601:RNA-Binding Proteins; D007288:Inosine; D046988:Proteasome Endopeptidase Complex; D000241:Adenosine