| Chromatin immunoprecipitation analyses demonstrated that T cell activation triggers in vivo binding of endogenous c Rel , c Jun , C / EBP beta , and HMG IC to the bfl 1 regulatory region , coincident with selective recruitment of coactivators TAFII 250 and p 300 , SWI / SNF chromatin remodeling factor component BRG 1 , and basal transcription factors TATA binding protein ( TBP ) and TFIIB , as well as hyperacetylation of histones H 3 and H 4 . ^^^ |