The TH1 cell lineage-determining transcription factor T-bet supresses TH2 gene expression by redistributing GATA3 away from TH2 genes [ChIP-seq]

Differentiation of progenitor cells into mature cell types is commonly associated with the expression of lineage-determining transcription factors (LD-TFs) specific to that lineage. In CD4+ T cells, T-bet dictates differentiation of the TH1 lineage, whereas GATA3 drives differentiation of the alternative TH2 lineage. LD-TFs, including T-bet and GATA3, are frequently co-expressed, both in vitro and in vivo. How co-expression of two mutually antagonistic LD-TFs affects their function and lineage determination is not known. By expressing T-bet and GATA3 separately or together, we show that T-bet sequesters GATA3 at its target sites, thereby removing GATA3 from TH2 genes. T-bet interacts with the GATA3 DNA binding domain, changing its DNA sequence binding preference. This mechanism allows T-bet to dominate and drive the TH1 gene expression program in the presence of the GATA3. We propose that redistribution of one LD-TF by another may be a common mechanism that could explain how specific cell fate choices can be made even in the presence of other TFs driving alternative differentiation pathways. Overall design: ChIP-seq for FLAG-T-bet and HA-GATA3 in T-bet-expressing, GATA3-expressing and T-bet and GATA3 co-expressing EL4 cells. ChIP-seq for H3K27ac in T-bet-expressing, GATA3-expressing and T-bet and GATA3 co-expressing EL4 cells and EL4 cells expressing neither protein.