Project description:This SuperSeries is composed of the following subset Series: GSE40684: Foxp3 exploits a preexistent enhancer landscape for regulatory T cell lineage specification [ChIP-Seq] GSE40685: Foxp3 exploits a preexistent enhancer landscape for regulatory T cell lineage specification [Expression] Refer to individual Series
Project description:Regulatory T (Treg) cells play crucial roles in suppressing deleterious immune response. Here, we investigate how mechanistically Treg cells are induced and stabilized via transcriptional regulation of Treg lineage–specifying factor Foxp3. Acetylation of histone tails in the Foxp3 locus is induced during Treg cell development and required in cis for the initiation of Foxp3 transcription. Upon induction, histone acetylation signal largely acts in trans to sustain Foxp3 transcription via multiple factors. Subsequently, Tet-mediated DNA demethylation of Foxp3 cis-regulatory elements particularly enhancer CNS2 increases chromatin accessibility and protein binding, drastically stabilizing Foxp3 transcription, although histone acetylation still regulates global gene expression. These processes transform stochastic Treg cell induction into a stable cell fate, with the former sensitive and latter resistant to genetic and environmental perturbations. Thus, our study reveals distinct roles of histone acetylation in Foxp3 induction and maintenance, reflecting sequential mechanical switches governing Treg cell lineage specification.
Project description:Regulatory T (Treg) cells play crucial roles in suppressing deleterious immune response. Here, we investigate how mechanistically Treg cells are induced and stabilized via transcriptional regulation of Treg lineage–specifying factor Foxp3. Acetylation of histone tails in the Foxp3 locus is induced during Treg cell development and required in cis for the initiation of Foxp3 transcription. Upon induction, histone acetylation signal largely acts in trans to sustain Foxp3 transcription via multiple factors. Subsequently, Tet-mediated DNA demethylation of Foxp3 cis-regulatory elements particularly enhancer CNS2 increases chromatin accessibility and protein binding, drastically stabilizing Foxp3 transcription, although histone acetylation still regulates global gene expression. These processes transform stochastic Treg cell induction into a stable cell fate, with the former sensitive and latter resistant to genetic and environmental perturbations. Thus, our study reveals distinct roles of histone acetylation in Foxp3 induction and maintenance, reflecting sequential mechanical switches governing Treg cell lineage specification.
Project description:Chromatin conformation reorganization is emerging as an important layer of regulation for gene expression and lineage specification. Yet, how lineage-specific transcription factors contribute to the establishment of cell type-specific 3D chromatin architecture in the immune cells remains unclear, especially for the late stages of T cell subset differentiation and maturation. Regulatory T cells (Treg) are mainly generated in the thymus as a subpopulation of T cells specializing in suppressing excessive immune responses. Here, by comprehensively mapping 3D chromatin organization during Treg cell differentiation, we show that Treg-specific chromatin structures were progressively established during its lineage specification, and highly associated with Treg signature gene expression. Additionally, the binding sites of Foxp3, a Treg lineage specifying transcription factor, were highly enriched at Treg-specific chromatin loop anchors. Further comparison of the chromatin interactions between wide-type Tregs versus Treg cells from Foxp3 knock-in/knockout or newly-generated Foxp3 domain-swap mutant mouse revealed that Foxp3 was essential for the establishment of Treg-specific 3D chromatin architecture, although it was not dependent on the formation of the Foxp3 domain-swapped dimer. These results highlighted an underappreciated role of Foxp3 in modulating Treg-specific 3D chromatin structure formation.
Project description:Chromatin conformation reorganization is emerging as an important layer of regulation for gene expression and lineage specification. Yet, how lineage-specific transcription factors contribute to the establishment of cell type-specific 3D chromatin architecture in the immune cells remains unclear, especially for the late stages of T cell subset differentiation and maturation. Regulatory T cells (Treg) are mainly generated in the thymus as a subpopulation of T cells specializing in suppressing excessive immune responses. Here, by comprehensively mapping 3D chromatin organization during Treg cell differentiation, we show that Treg-specific chromatin structures were progressively established during its lineage specification, and highly associated with Treg signature gene expression. Additionally, the binding sites of Foxp3, a Treg lineage specifying transcription factor, were highly enriched at Treg-specific chromatin loop anchors. Further comparison of the chromatin interactions between wide-type Tregs versus Treg cells from Foxp3 knock-in/knockout or newly-generated Foxp3 domain-swap mutant mouse revealed that Foxp3 was essential for the establishment of Treg-specific 3D chromatin architecture, although it was not dependent on the formation of the Foxp3 domain-swapped dimer. These results highlighted an underappreciated role of Foxp3 in modulating Treg-specific 3D chromatin structure formation.
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers lacking in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape. Four transcription factors (Foxp3, Ets1, Elf1, and Cbfb) were immunoprecipated while crosslinked to chromatin. These experiments were then combined with DNase-seq data (being uploaded separately as part of ENCODE project) to find that Foxp3 binds exclusively to open chromatin. Data was also leveraged from GSE40657 and GSE33653.