Essential role of the Pax5 C-terminal domain in controlling B cell commitment and development

Pax5 controls B-cell commitment, development and immunity by repressing B-lineage-inappropriate genes and activating B-cell-specific genes. In addition to the N-terminal DNA-binding paired domain, Pax5 contains a conserved octapeptide, partial homeodomain and C-terminal sequences with transactivating and inhibitory potential. To understand how the C-terminal domains of Pax5 contribute to the repression and activation function of Pax5, we performed Pax5 pulldown combined with mass spectrometry to identify coactivator or corepressor complexes that bind to the C-terminal regions of Pax5.