title: B cell lymphoma (Bcl)-2 protein is the major determinant in bcl-2 adenine-uridine-rich element turnover overcoming HuR activity.
abstract: In the 3'-untranslated region, the destabilizing adenine-uridine (AU)-rich elements (AREs) control the expression of several transcripts through interactions with ARE-binding proteins (AUBPs) and RNA degradation machinery. Although the fundamental role for AUBPs and associated factors in eliciting ARE-dependent degradation of cognate mRNAs has been recently highlighted, the molecular mechanisms underlying the specific regulation of individual mRNA turnover have not yet been fully elucidated. Here we focused on the post-transcriptional regulation of bcl-2 mRNA in human cell lines under different conditions and genetic backgrounds. In the context of an AUBPs silencing approach, HuR knockdown reduced the expression of endogenous bcl-2, whereas unexpectedly, a bcl-2 ARE-reporter transcript increased significantly, suggesting that HuR expression has opposite effects on endogenous and ectopic bcl-2 ARE. Moreover, evidence was provided for the essential, specific and dose-dependent role of the Bcl-2 protein in regulating the decay kinetics of its own mRNA, as ascertained by a luciferase reporter system. Altogether, the data support a model whereby the Bcl-2 protein is the major determinant of its own ARE-dependent transcript half-life in living cells and its effect overcomes the activity of ARE-binding proteins.
authors.affiliation: Department of Pharmacology, Università degli Studi di Milano, 20129 Milan.
authors.forename: Laura
authors.initials: L
authors.lastname: Ghisolfi
authors.forename: Angela
authors.initials: A
authors.lastname: Calastretti
authors.forename: Sara
authors.initials: S
authors.lastname: Franzi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Canti
authors.forename: Martino
authors.initials: M
authors.lastname: Donnini
authors.forename: Sergio
authors.initials: S
authors.lastname: Capaccioli
authors.forename: Angelo
authors.initials: A
authors.lastname: Nicolin
authors.forename: Annamaria
authors.initials: A
authors.lastname: Bevilacqua
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism*; D002460:Cell Line; D002999:Clone Cells; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D020868:Gene Silencing; D017930:Genes, Reporter; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D008156:Luciferases / Q000378:metabolism; D039102:Poly(A)-Binding Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics*; D015203:Reproducibility of Results; D000074019:T-Cell Intracellular Antigen-1; D014162:Transfection
chemical_list: D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; C000630986:HNRNPD protein, human; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; D039102:Poly(A)-Binding Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D000074019:T-Cell Intracellular Antigen-1; C071558:TIA1 protein, human; D008156:Luciferases