Role of Coactivators in Transcription Processes

According to Kim, Hsiao & Kraus (2001), P300 has divided int four distinctive regions, and all the parts play a vital role in the process of transcription and activation procedures to achieve gene transcription. The use of p300 to test the ability to affect AdE4, which is a core promoter in the process of transcription. The findings, however, indicate that when p 300 is not added, it causes the GTS -E1A, to prevent the transcription activation process by five times. However, in the addition of p300, it was able to stop the inhibition of the transcription process by the GTS -E1A. Hence the availability of p 300 enables the AdE4 major promoter in the process of transcription as indicated by ( Kim, Hsiao & Kraus 2001). Consequently, the GTS-E1A shows to inhibit activation of p300 in the Hella cell nuclear extract, this was evident when and addition of p300 caused the transcription process to occur which had been initially inhibited by GST-E1A. 

The activity of P300 is necessary and essential in the process of transcription; on the other hand, P 300/CBP act as co-factors in for nuclear hormone receptors. However, the activity of p300 is not necessary for nuclear receptors. To prove this, Kim, Hsiao & Kraus (2001), indicate that the activity of the inhibitory of HAT is vital because of its ability to inhibit the actions of activation that depend on the p300. Consequently, the N terminal is necessary for the block of nuclear receptors signaling; hence, multiple interactions may play an essential role in the actions E1A in Vevo. Therefore the activity of HAT resulting from p300/CBP is crucial for the process of transcription and not the function of nuclear hormone receptors. Additionally, the inhibition of this activity is primarily due to the EA1 blocking the action of the PCAF complex, Kim, Hsiao & Kraus (2001), suggest that these results with a combined inhibition of p300 demonstrate a possible restraint to modification of chromatin and regulation of transcriptional procedures. 

Reference

Kim, M. Y., Hsiao, S. J., & Kraus, W. L. (2001). A role for coactivators and histone acetylation in estrogen receptor α ‐ mediated transcription initiation. The EMBO journal, 20(21), 6084-6094.