RAG-mediated DNA breaks attenuate PU.1 activity in early B cells through activation of a SPIC-BCLAF1 complex [ChIP-Seq]

RAG DSBs trigger ATM-dependent induction of SPIC, an ETS family transcriptional repressor with significant homology to PU.1. RAG DSB-mediated expression of SPIC results in displacement of PU.1 throughout the genome and induction of broad transcriptional changes in pre B cells. SPIC also binds and recruits a unique partner, BCLAF1 to gene regulatory elements that regulate expression of key B cell developmental genes. ChIP was performed using anti-PU.1, anti-HA, and anti-BCLAF1