Related Experiment Video
Updated: Jul 30, 2026
11:07
Biochemical Reconstitution of Steroid Receptor•Hsp90 Protein Complexes and Reactivation of Ligand Binding
Published on: September 21, 2011
Steroid receptor coactivator-1 is a histone acetyltransferase
T E Spencer1, G Jenster, M M Burcin
1Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Nature
|September 20, 1997
Summary
Steroid receptor coactivator SRC-1 has histone acetyltransferase activity, aiding gene transcription. This activity, along with PCAF, helps overcome chromatin repression, enabling gene activation.
Area of Science:
- Molecular Biology
- Epigenetics
- Gene Regulation
Background:
- Steroid receptors and coactivators typically enhance gene expression by forming transcription complexes.
- Accessing repressed chromatin remains a key question in understanding gene activation in vivo.
- Histone acetyltransferases (HATs) are known to counteract chromatin's inhibitory effects on transcription.
Purpose of the Study:
- To investigate the role of steroid receptor coactivator SRC-1 in chromatin modulation.
- To determine if SRC-1 possesses intrinsic histone acetyltransferase (HAT) activity.
- To explore the interaction between SRC-1, PCAF, and histone acetylation in gene transcription.
Main Methods:
- Biochemical assays to assess HAT activity of SRC-1.
- Protein interaction studies to examine SRC-1 and PCAF binding.
- Analysis of histone acetylation patterns on specific gene promoters.
Main Results:
- SRC-1 exhibits intrinsic HAT activity, primarily targeting histones H3 and H4.
- SRC-1 interacts with another HAT, p300/CBP-associated factor (PCAF).
- Ligand binding to steroid receptors may trigger SRC-1 and PCAF-mediated histone acetylation.
Conclusions:
- SRC-1's HAT activity is crucial for overcoming chromatin repression.
- Coordinated action of SRC-1 and PCAF facilitates transcription factor access to repressed chromatin.
- This mechanism enhances steroid receptor-mediated gene activation and increases specific gene transcription.
Related Concept Videos
02:32Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
02:42Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
02:32Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...