title: Post-transcriptional regulation of Transforming Growth Factor Beta-1 by microRNA-744.
abstract: Transforming Growth Factor Beta-1 (TGF-β1) is a pleiotropic cytokine that is of central importance in wound healing, inflammation, and in key pathological processes including cancer and progressive tissue fibrosis. TGF-β1 is post-transcriptionally regulated, but the underlying mechanisms remain incompletely defined. Previously, we have extensively delineated post-transcriptional regulation of TGF-β1 synthesis in the kidney, with evidence for relief of translational repression in proximal tubular cells in the context of diabetic nephropathy. In this study, we have investigated the role of the TGF-β1 3'Untranslated Region (3'UTR). Two different 3'UTR lengths have been reported for TGF-β1, of 543 and 137 nucleotides. Absolute quantification showed that, while both UTR lengths were detectable in various human cell types and in a broad range of tissues, the short form predominated in the kidney and elsewhere. Expression of both forms was up-regulated following auto-induction by TGF-β1, but the short:long UTR ratio remained constant. Incorporation of the short UTR into a luciferase reporter vector significantly reduced reporter protein synthesis without major effect on RNA amount, suggesting post-transcriptional inhibition. In silico approaches identified multiple binding sites for miR-744 located in the proximal TGF-β1 3'UTR. A screen in RNA from human tissues showed widespread miR-744 expression. miR-744 transfection inhibited endogenous TGF-β1 synthesis, while direct targeting of TGF-β1 was shown in separate experiments, in which miR-744 decreased TGF-β1 3'UTR reporter activity. This work identifies miR-744-directed post-transcriptional regulation of TGF-β1 which, given the pleiotropic nature of cellular responses to TGF-β1, is potentially widely significant.
authors: School of Medicine, Institute of Nephrology, Cardiff University, Cardiff, Wales, United Kingdom.
authors: John
authors: J
authors: Martin
authors: Robert H
authors: RH
authors: Jenkins
authors: Rasha
authors: R
authors: Bennagi
authors: Aleksandra
authors: A
authors: Krupa
authors: Aled O
authors: AO
authors: Phillips
authors: Timothy
authors: T
authors: Bowen
authors: Donald J
authors: DJ
authors: Fraser
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D056915:DNA Copy Number Variations / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; C552243:MIRN663 microRNA, human; C569733:MIRN744 microRNA, human; D035683:MicroRNAs; D009711:Nucleotides; D020033:Protein Isoforms; D053773:Transforming Growth Factor beta1