GSE99595
Genome wide mapping of accessible chromatin in CD4+ T-cells during Th2 immune responses
Naïve CD4+ T-helper cells differentiate into Th2 effector cells during asthma and helminth (worm) infection. Here, we report that mice lacking the transcription factor Bcl11b in mature CD4+ T-cells are incapable of mounting an effective Th2 response in asthma and worm infection, with a major reduction of Th2 cytokine secretion and GATA3 expression. We found that Bcl11b exerts its role in Th2 differentiation through several avenues: (1) association with intronic regions at the Gata3 locus, sustaining GATA3 expression; (2) binding to and restricting chromatin accessibility at the Il4 silencer, located at hypersensitivity site (HS) IV; and (3) restricting Runx3 expression by association with a regulatory region 5' of Runx3. Thus, in the absence of Bcl11b, the reduction in GATA3 levels combined with increased Runx3 levels and activity at Il4 HS IV silencer and consequently diminished IL-4 expression. This results in reduced chromatin opening at the Th2 locus control region (LCR), Il13 and Il5 promoters, subsequently preventing expression of Th2 cytokine genes and Th2 differentiation. Our results establish a novel role for Bcl11b in the regulatory loop critical for licensing the Th2 program in vivo. Overall design: Examination of the changes caused to chromatin accessibility during allergic asthma by the removal of Bcl11b