title: BCL11B is required for positive selection and survival of double-positive thymocytes.
abstract: Transcriptional control of gene expression in double-positive (DP) thymocytes remains poorly understood. We show that the transcription factor BCL11B plays a critical role in DP thymocytes by controlling positive selection of both CD4 and CD8 lineages. BCL11B-deficient DP thymocytes rearrange T cell receptor (TCR) alpha; however, they display impaired proximal TCR signaling and attenuated extracellular signal-regulated kinase phosphorylation and calcium flux, which are all required for initiation of positive selection. Further, provision of transgenic TCRs did not improve positive selection of BCL11B-deficient DP thymocytes. BCL11B-deficient DP thymocytes have altered expression of genes with a role in positive selection, TCR signaling, and other signaling pathways intersecting the TCR, which may account for the defect. BCL11B-deficient DP thymocytes also presented increased susceptibility to spontaneous apoptosis associated with high levels of cleaved caspase-3 and an altered balance of proapoptotic/prosurvival factors. This latter susceptibility was manifested even in the absence of TCR signaling and was only partially rescued by provision of the BCL2 transgene, indicating that control of DP thymocyte survival by BCL11B is nonredundant and, at least in part, independent of BCL2 prosurvival factors.
authors.affiliation: Center for Cell Biology and Cancer Research, Albany Medical College, Albany, NY 12208, USA.
authors.forename: Diana I
authors.initials: DI
authors.lastname: Albu
authors.forename: Dongyun
authors.initials: D
authors.lastname: Feng
authors.forename: Debarati
authors.initials: D
authors.lastname: Bhattacharya
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Jenkins
authors.forename: Neal G
authors.initials: NG
authors.lastname: Copeland
authors.forename: Pentao
authors.initials: P
authors.lastname: Liu
authors.forename: Dorina
authors.initials: D
authors.lastname: Avram
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D016366:Open Reading Frames; D011518:Proto-Oncogene Proteins / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D013950:Thymus Gland / Q000033:anatomy & histology / Q000276:immunology; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: C511143:Bcl11b protein, mouse; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; C052617:Bcl2 protein, mouse