HISTONE-LIKE TAFS WITHIN THE PCAF HISTONE ACETYLASE COMPLEX

PCAF histone acetylase plays a role in regulation of transcription, ce ll cycle progression, and differentiation. Here, we show that PCAF is found in a complex consisting of more than 20 distinct polypeptides. S trikingly, some polypeptides are identical to TBP-associated factors ( TAFs), which are subunits of TFIID. Like TFIID, histone fold-containin g factors are present within the PCAF complex. The histone H3- and H2B -like subunits within the PCAF complex are identical to those within T FIID, namely, hTAF(II)31 and hTAF(II)20/15, respectively. The PCAF com plex has a novel histone H4-like subunit with similarity to hTAF(II)80 that interacts with the histone H3-like domain of hTAF(II)31. Moreove r, the PCAF complex has a novel subunit with WD40 repeats having a sim ilarity to hTAF(II)100.