title: Analysis of the complex genomic structure of Bcl-x and its relationship to Bcl-x(gamma) expression after CD28-dependent costimulation.
abstract: The Bcl-x(gamma) cytosolic protein is essential for costimulatory activity after CD3/CD28 coligation. Here we delineate the Bcl-x(gamma)/Bcl-x genomic organization and the molecular mechanism that allows expression. We show that exon 4 of the Bcl-x gene encodes the unique C-terminal end of the Bcl-x(gamma) molecule while exons 5, 6, 7 and 8 are differentially transcribed to yield three alternative Bcl-x(gamma) 3' untranslated regions (UTR). CD28-dependent signals may increase levels of Bcl-x(gamma) protein through induction of an alternatively-spliced Bcl-x(gamma) 3' UTR that contains stem loop structures that stabilize Bcl-x(gamma) RNA. The ability receptor-induced signals to regulate the splicing pattern of the complex Bcl-x gene may allow T-cells to respond appropriately to antigenic stimuli.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Yang
authors.forename: Qunrui
authors.initials: Q
authors.lastname: Ye
authors.forename: Barry
authors.initials: B
authors.lastname: Press
authors.forename: Rui-Zhu
authors.initials: RZ
authors.lastname: Han
authors.forename: Craig H
authors.initials: CH
authors.lastname: Bassing
authors.forename: Barry P
authors.initials: BP
authors.lastname: Sleckman
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Alt
authors.forename: Harvey
authors.initials: H
authors.lastname: Cantor
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology; D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D018106:CD28 Antigens / Q000502:physiology*; D005091:Exons; D007438:Introns; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics*; D013601:T-Lymphocytes / Q000378:metabolism; D014158:Transcription, Genetic; D051020:bcl-X Protein
chemical_list: D020413:3' Untranslated Regions; C494812:Bcl2l1 protein, mouse; D018106:CD28 Antigens; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein