Project description:T-cell receptor (TCR) signals play a critical role in guiding selected thymocytes to distinct lineages by activating genes for transcription factors, such as ThPOK and Runx3, for the helper- or cytotoxic-lineage, respectively. Here we show that Bcl11b, known as an early T-lineage commitment factor, is essential for proper expression of ThPOK and Runx3. Loss of Bcl11b resulted in premature and random expression of these specification factors, leading to lineage scrambling that was disconnected from TCR restriction by MHC. Early Thpok repression by Bcl11b is independent of its known transcriptional silencer, but requires the C-terminal zinc-finger of Bcl11b. Collectively, our findings shed new light on the role of Bcl11b in priming lineage-specifying genes to integrate TCR signals into a subsequent developmental program that dissects effector lineages.
Project description:Review on the role of Bcl11b in thymus and periphery and impact on diseases RNA was extracted from DP thymocytes of bcl11bf/fCd4cre/tcra-/- and tcra-/- mice. Tcra-/- mice only have preselected DP thymocytes. Such mice were used to determine the role of Bcl11b before selection, considering the defective positive selection in bcl11bf/fcd4cre mice. RNA was isolated and submitted for library generation and microarray analysis to determine expression profile of bcl11b-/- preselected DP thymocytes.
Project description:T-cell receptor (TCR) signals play a critical role in guiding selected thymocytes to distinct lineages by activating genes for transcription factors, such as ThPOK and Runx3, for the helper- or cytotoxic-lineage, respectively. Here we show that Bcl11b, known as an early T-lineage commitment factor, is essential for proper expression of ThPOK and Runx3. Loss of Bcl11b resulted in premature and random expression of these specification factors, leading to lineage scrambling that was disconnected from TCR restriction by MHC. Early Thpok repression by Bcl11b is independent of its known transcriptional silencer, but requires the C-terminal zinc-finger of Bcl11b. Collectively, our findings shed new light on the role of Bcl11b in priming lineage-specifying genes to integrate TCR signals into a subsequent developmental program that dissects effector lineages.
Project description:BCL11B and Ikaros, transcription factors essential to normal development and maturation of T cells are associated with the Mi2-beta NuRD complex in CD4+ CD8+ double-positive thymocytes.
Project description:The aim of this study is to survey global gene expression of total thymocytes from wild-type mice and Atg16l1 mutant (hypomorph) mice.
Project description:The function of Dnmt3b, of which deregulated activity is linked to several human pathologies, was studied using Dnmt3b hypomorphic mutant mice with reduced catalytic activity. Microarray analysis of deregulated expression programs in the hypomorphic Dnmt3b mutant mice (m3/m24) was combined to an analysis of the molecular mechanisms involved in the illegitimate activation of a specific set of genes.
Project description:Background: Severe combined immunodeficiency (SCID) is characterized by arrested T lymphocyte production and B lymphocyte dysfunction, resulting in life-threatening infections. Early diagnosis of SCID through population-based newborn screening (NBS) optimizes clinical management and outcomes, and also permits identification of previously unknown factors essential for human lymphocyte development. Methods: SCID was detected, prior to onset of infections, by NBS of T cell receptor excision circles, a biomarker for thymic output. Upon confirmation, the affected baby was treated by allogeneic hematopoietic cell transplantation (HCT). The genetic cause was sought by exome sequencing of the patient and parents, followed by functional analysis of a prioritized candidate gene using human hematopoietic stem cells (HSC) and zebrafish embryos. Results: An infant with leaky SCID, craniofacial and dermal abnormalities, and absent corpus callosum had his immune deficit fully corrected by HCT. Exome sequencing revealed a heterozygous, de novo, missense mutation pN441K in BCL11B. The mutant Bcl11b protein had dominant negative activity, abrogating the ability of wild type Bcl11b to bind DNA, arresting T cell lineage development and disrupting HSC migration, revealing a novel function of Bcl11b. The patientâs defects, recapitulated in Bcl11b-deficient zebrafish, were reversed by ectopic expression of intact, but not mutant, human BCL11B. Conclusions: Newborn screening facilitated treatment and identification of a novel etiology for human SCID. Coupling exome sequencing with candidate gene evaluation in human HSC and in zebrafish revealed that a constitutional BCL11B mutation causes human multisystem anomalies with SCID, while also revealing a novel, pre-thymic role for Bcl11b in hematopoietic progenitors. 3 samples were analyzed in duplicate, Sample 1 was human HSC transduced with GFP only lentivirus which served as controls, Sample 2 was human HSC transduced with lentivirus expressing FLAG-tagged WT BCL11B and GFP, Sample 3 was human HSC transduced with lentivirus expressing FLAG-tagged mutant BCL11B and GFP