Transcriptional activation domain of p300/CBP-associated factor(P/CAF)

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In eukaryores, transcription of mRNA-encoding classII genes involves the ordered recruitment of general factors and the RNA polymerase II holoenzyme into the basal transcription pre-initiation complex on promoter.The transcription is efficiently enhanced by transcriptional activators which bind to specific DNA sequences outside of the core promoter.Sequence-specific activators work in conjunction with other factors which do not bind DNA directly.These factors are termed co-activators and are recruited to promoters via their interaction with the DNA-bound transcription factors.P/CAF was originally identified as a p300/CBP-binding protein by virtue of its sequence similarity to a yeast histone acetyltransferase (HAT), namely yGCN5.In addition, P/CAF interacts with other co-activators such as ACIR and SRC-1 which are also HAT.In this study, I focused on the function of P/CAF in the transcriptional regulation and investigated the transcriptional activation domain of P/CAF.In order to examine the activation function of P/CAF, I expressed various regions of P/CAF as GALA DNA binding domain in yeast.P/CAF indeed worked as a transcriptional activator protein in yeast and the region of amino acids 366-654 was necessary for activation function.As this region is identical to the HAT domain, the activation function of P/CAF might be related to the acetylation of histones.On the other hand, the interaction of P/CAF with CBP was independent on the activation domain. The complex formation of co-activators in vitro was also examined using surface plasmon resonance anaysis.