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Unlocking the mechanisms of transcription factor YY1: are chromatin modifying enzymes the key?
1Molecular Oncology Program, H. Lee Moffitt Cancer Center & Research Institute, University of South Florida, Tampa, FL 33612, USA.
Abstract:
The transcription factor YY1 is a complex protein that is involved in repressing and activating a diverse number of promoters. Numerous studies have attempted to understand how this one factor can act both as a repressor and an activator in such a wide set of different contexts. The fact that YY1 interacts with a number of key regulatory proteins (e.g. TBP, TFIIB, TAFII55, Sp1, and E1A) has suggested that these interactions are important for determining which particular function of YY1 is displayed at a specific promoter. Two groups of proteins, previously known to function as corepressors and coactivators, that now seem likely to modulate YY1's functions, are the histone deacetylases (HDAC) and histone acetyltransferases (HAT). These two groups of enzymes modify histones, and this modification is proposed to alter chromatin structure. Acetylated histones are typically localized to active chromatin while deacetylated histones colocalize with transcriptionally inactive chromatin. When these enzymes are directed to a promoter through a DNA binding factor such as YY1, that promoter can be activated or repressed. This review will discuss the recent work dealing with the different proteins that interact with YY1, with particular emphasis on ones that modify chromatin, and how they could be involved in regulating YY1's activities.
Insights
The transcription factor YY1 can activate or repress gene activity by interacting with regulatory proteins. Histone-modifying enzymes like HDACs and HATs are key to understanding YY1
Area of Science:
- Molecular Biology
- Gene Regulation
- Epigenetics
Background:
- The transcription factor Yin Yang 1 (YY1) exhibits dual roles as both a repressor and activator of gene transcription.
- YY1's diverse functions are thought to be mediated by interactions with various regulatory proteins, including transcription factors and cofactors.
- Histone deacetylases (HDACs) and histone acetyltransferases (HATs) are epigenetic modifiers that influence chromatin structure and gene expression.
Purpose of the Study:
- To review recent findings on proteins interacting with YY1.
- To emphasize the role of chromatin-modifying enzymes in regulating YY1 activity.
- To elucidate the mechanisms by which YY1's functions are modulated at specific promoters.
Main Methods:
- Literature review of studies investigating YY1 interactions.
- Analysis of research on histone deacetylases (HDACs) and histone acetyltransferases (HATs) in relation to YY1.
- Examination of proposed models for YY1-mediated gene regulation via chromatin modification.
Main Results:
- YY1 interacts with a multitude of proteins, including TBP, TFIIB, TAFII55, Sp1, and E1A, influencing its regulatory outcome.
- HDACs and HATs emerge as critical modulators of YY1 function, likely by altering local chromatin structure.
- Acetylation/deacetylation of histones, directed by YY1-interacting enzymes, correlates with active or inactive chromatin states, respectively.
Conclusions:
- Interactions with specific proteins, particularly chromatin-modifying enzymes, dictate whether YY1 activates or represses transcription.
- The interplay between YY1 and HDACs/HATs provides a mechanism for context-dependent gene regulation.
- Further research into these interactions is crucial for a comprehensive understanding of YY1's role in gene expression.