Loss of the FOXP1 transcription factor leads to deregulation of B lymphocyte development and function at multiple stages

This study examined the loss of Foxp1 in B cells at different stages. RNA-seq was performed to examine gene expression differences fromB cells from wildtype and Foxp1 cKO spleens. We found strong enrichment for signatures related to down-regulation of immune responses, apoptosis and germinal center biology, including direct activation of Bcl6 and downregulation of Aicda/AID, the primary effector of SHM and CSR. These observations support a role for FOXP1 as a direct transcriptional regulator at key steps underlying B cell development in the mouse. Overall design: Splenic B cell mRNA profiles were compared among WT and CD19creFoxp1 cKO C57Bl/6 mice