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Human p300 protein is a coactivator for the transcription factor MyoD
W Yuan1, G Condorelli, M Caruso
1Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Abstract:
Human p300 protein is a cellular target of adenoviral E1A oncoprotein and a potential transcriptional coactivator. Both p300 and Rb family protein-binding regions of E1A are required for the repression of muscle gene expression, which is regulated by MyoD family transactivators. This implies that p300 is involved in MyoD-dependent transactivation. We show that the repression of MyoD-mediated E box (MyoD consensus) reporter activity by E1A is correlated with its interaction with p300, indicating that p300 participates in MyoD-dependent transactivation. In addition, p300 is able to interact both in vivo and in vitro with MyoD through a portion at the carboxyl-terminal cysteine/histidine-rich domain and associates with the components of the basal transcriptional complex through its two separate transactivation domains at the amino and carboxyl termini. Consistent with its role as a coactivator, p300 potentiates MyoD-activated transcription.
Insights
Human p300 protein acts as a transcriptional coactivator, participating in MyoD-dependent gene activation. Adenoviral E1A oncoprotein
Area of Science:
- Molecular Biology
- Cellular Biology
- Virology
Background:
- Human p300 protein is a cellular target of adenoviral E1A oncoprotein.
- p300 is a potential transcriptional coactivator involved in gene regulation.
- Adenoviral E1A oncoprotein interacts with p300 and Rb family proteins.
Purpose of the Study:
- To investigate the role of p300 in MyoD-dependent transactivation.
- To determine the interaction between p300 and MyoD.
- To elucidate the mechanism by which E1A represses muscle gene expression.
Main Methods:
- Co-immunoprecipitation assays to study protein interactions in vivo and in vitro.
- Reporter gene assays to measure MyoD-mediated transcriptional activity.
- Analysis of protein domains involved in p300-MyoD interaction.
Main Results:
- Adenoviral E1A-mediated repression of MyoD reporter activity correlates with p300 interaction.
- p300 interacts with MyoD through its carboxyl-terminal cysteine/histidine-rich domain.
- p300 associates with basal transcriptional complex components via its transactivation domains.
- p300 potentiates MyoD-activated transcription, confirming its coactivator role.
Conclusions:
- p300 is a crucial coactivator in MyoD-dependent transcription.
- Adenoviral E1A interferes with MyoD function by interacting with p300.
- Understanding p300's role in transcription is vital for studying viral oncogenesis and muscle gene regulation.