GSE161840
OBF1 and Oct factors control the germinal center transcriptional program (RNA-seq - mouse)
OBF1 is a specific coactivator of the POU family transcription factors OCT1 and OCT2. OBF1 and OCT2 are B cell-specific and indispensable for germinal center (GC) formation, but their mechanism of action is unclear. Here, we show by ChIP-seq that OBF1 extensively colocalizes with OCT1 and OCT2 and stabilizes their binding. We found that these factors also often colocalize with transcription factors of the ETS family, such as PU.1 and ETS1. Furthermore, we showed that OBF1, OCT2 and OCT1 bind widely to the promoters or enhancers of genes involved in GC formation, such as the master regulators Bcl6 and Foxo1. shRNA knockdown experiments demonstrated that OCT1, OCT2 and OBF1 are essential for proliferation of GC-derived lymphoma cell lines. OBF1 downregulation disrupts the GC transcriptional program: genes involved in GC maintenance -such as BCL6- are downregulated, while genes related to exit from the GC program are upregulated. Ectopic expression of BCL6 does not restore the proliferation of GC-derived Raji cells depleted of OBF1 unless IRF4 is also depleted, indicating that OBF1 controls a critical regulatory node in GC differentiation. Overall design: RNA-seq of mouse PU1 KO and OBF1KO CD19+ B cells under LPS stimulation