title: The adipogenic transcriptional cofactor ZNF638 interacts with splicing regulators and influences alternative splicing.
abstract: Increasing evidence indicates that transcription and alternative splicing are coordinated processes; however, our knowledge of specific factors implicated in both functions during the process of adipocyte differentiation is limited. We have previously demonstrated that the zinc finger protein ZNF638 plays a role as a transcriptional coregulator of adipocyte differentiation via induction of PPARγ in cooperation with CCAAT/enhancer binding proteins (C/EBPs). Here we provide new evidence that ZNF638 is localized in nuclear bodies enriched with splicing factors, and through biochemical purification of ZNF638's interacting proteins in adipocytes and mass spectrometry analysis, we show that ZNF638 interacts with splicing regulators. Functional analysis of the effects of ectopic ZNF638 expression on a minigene reporter demonstrated that ZNF638 is sufficient to promote alternative splicing, a function enhanced through its recruitment to the minigene promoter at C/EBP responsive elements via C/EBP proteins. Structure-function analysis revealed that the arginine/serine-rich motif and the C-terminal zinc finger domain required for speckle localization are necessary for the adipocyte differentiation function of ZNF638 and for the regulation of the levels of alternatively spliced isoforms of lipin1 and nuclear receptor co-repressor 1. Overall, our data demonstrate that ZNF638 participates in splicing decisions and that it may control adipogenesis through regulation of the relative amounts of differentiation-specific isoforms.
authors.affiliation: Genetics of Development and Disease Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Chen
authors.initials: C
authors.lastname: Du
authors.affiliation: Genetics of Development and Disease Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Xinran
authors.initials: X
authors.lastname: Ma
authors.affiliation: Genetics of Development and Disease Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Meruvu
authors.affiliation: Genetics of Development and Disease Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Lynne
authors.initials: L
authors.lastname: Hugendubler
authors.affiliation: Genetics of Development and Disease Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Mueller
mesh_terms: D041721:3T3-L1 Cells; D021581:Active Transport, Cell Nucleus; D050156:Adipogenesis; D017398:Alternative Splicing; D000818:Animals; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C000602512:ZNF638 protein, mouse
keywords: adipocyte differentiation; minigene reporter; nuclear speckles; transcriptional coactivator