Transcriptional synergy between Tat and PCAF is dependent on the binding of acetylated Tat to the PCAF bromodomain

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Dorr, Alexander, et al. “Transcriptional synergy between Tat and PCAF is dependent on the binding of acetylated Tat to the PCAF bromodomain.” The EMBO Journal 21.11 (2002): 2715-2723.
The article, “Transcriptional synergy between Tat and PCAF is dependent on the binding of acetylated Tat to the PCAF bromodomain,” by Dorr Alexander et al. seeks to test the probability of acetylated Tat’s interaction with a bromodomain. The research question is to address the acetylated Tat-PCAF interaction and a subsequent examination of “its relevance to the transcriptional activation process mediated by Tat” (Dorr et al. 2715).
It is distinctly clear from the abstract that this is a very vital issue, concerning the essential role that the HIV Tat protein plays in the promotion of efficient viral transcripts elongation. The authors introduce the subject through citing the relevant literature regarding transactivator role played by the HIV Tat protein, who’s binding to the Tat-responsive element (TAR) would stimulate full-length HIV transcripts to be produced. The TAR/Tat axis is critical in determining the viral replication dynamics in cells that are infected. They infer to previous experiments that have uniquely highlighted the Tat role in this HIV transcription as a coordinative adaptor to other factors in the HIV promoter (Wei et al. 451-460).
Another factor of essence is the transcriptional regulation role played by the reversible lysine residues acetylation.

For them to test the probability of interaction between acetylated Tat and the bromodomain, the researchers examined various proteins containing bromodomain. This is necessary to get results from different tests, increasing chances of the reliability of the findings, and helping to develop the proper relationship. This included establishing whether “PCAF, the Tat, and transcriptional co-activator functionally interact with the HIV promoter through co-transfection of suitable protein vectors” (Dorr et al. 2716). The transfected cells’ cellular extracts were then immunoprecipitated and the resulting material analyzed by western blotting for the PCAF and Tat. The authors also conducted another test by replacing with arginines the Tat residues K50 and K51. Further assessment of the PCAF bromodomain role in Tat activation involved raising “a polyclonal antiserum using recombinant PCAF bromodomain in Escherichia coli” (Dorr et al. 2716).
The study results and consequent discussion present the experimental evidence of the specific interaction between acetylated Tat and PCAF, which is a direct process under the mediation of the PCAF’s bromodomain. This interaction and subsequent synergy lead to activation of the HIV promoter. Their observations led to their conclusion of the establishment of a “novel protein-protein interaction” by the acetylation of Tat on its surface which is necessary for the HIV promoter’s transcriptional activation (Dorr et al. 2720).
The article is entirely clear from the beginning regarding its objectives.There is a concise introduction, concerning the relevant literature on the subject which they intend to investigate. It gives the leader a clear gist on the background and shapes his or her mind to what is expected from the study. The multiple tests done to justify the results obtained help to remove doubt in the mind of any reader regarding the study’s reliability. It is a well-written article with a convincing theoretical background and practical approach to the research problem.

Works Cited
Dorr, Alexander, et al. “Transcriptional synergy between Tat and PCAF is dependent on the binding of acetylated Tat to the PCAF bromodomain.” The EMBO Journal 21.11 (2002): 2715-2723.
Wei, Ping, et al. “A novel CDK9-associated C-type cyclin interacts directly with HIV-1 Tat and mediates its high-affinity, loop-specific binding to TAR RNA.” Cell 92.4 (1998): 451-462.