DEPENDENCE OF BSAP REPRESSOR AND ACTIVATOR FUNCTIONS ON BSAP CONCENTRATION

During a B cell immune response, the transcription factor BSAP maintai ns its activator functions but is relieved of its repressor functions. This selective targeting of BSAP activities was shown to be regulated by a concentration-dependent mechanism whereby activator motifs for B SAP had a 20-fold higher binding affinity than repressor motifs. An ex change of activator and repressor motifs, however, showed that the con text of the motif, rather than the affinity, determined whether BSAP o perated as an activator or repressor.