Related Experiment Video
Updated: Jun 17, 2026
10:28
Repressing Gene Transcription by Redirecting Cellular Machinery with Chemical Epigenetic Modifiers
Published on: September 20, 2018
Antagonizing Polycomb group-mediated gene repression by chromatin remodelers
Claudia Köhler1, Ernst Aichinger
1Department of Biology and Zurich-Basel Plant Science Center, Swiss Federal Institute of Technology, ETH Centre, Zurich, Switzerland. koehlerc@ethz.ch
Epigenetics
|January 20, 2010
Summary
Polycomb group (PcG) proteins maintain cellular identity through epigenetic repression. Chromatin remodelers with trithorax group (trxG)-like functions in Arabidopsis reveal conserved antagonistic mechanisms in eukaryotes.
Area of Science:
- Epigenetics and Gene Regulation
- Chromatin Biology
- Developmental Biology
Background:
- Cellular identity relies on epigenetic mechanisms that preserve cell-type specific transcription.
- Polycomb group (PcG) proteins are crucial for maintaining cellular identity by repressing developmental genes via chromatin modification.
- Trithorax group (trxG) proteins antagonize PcG-mediated repression, but their molecular basis remains largely unknown.
Purpose of the Study:
- To explore the function of chromatin regulatory proteins in antagonizing PcG-mediated repression.
- To investigate the role of Chromodomain-Helicase-DNA-binding (CHD) subfamily proteins in Arabidopsis.
- To discuss the implications of these findings for understanding conserved gene regulation in eukaryotes.
Main Methods:
- Review of recent research on trxG proteins in Arabidopsis.
- Analysis of ATP-dependent chromatin remodeling factors within the CHD subfamily.
- Discussion of evolutionary conservation of PcG/trxG gene regulation.
Main Results:
- Recent studies identified ATP-dependent chromatin remodelers of the CHD subfamily exhibiting trxG-like functions in Arabidopsis.
- These findings suggest a conserved molecular mechanism for antagonizing PcG repression.
Conclusions:
- Chromatin remodeling factors play a significant role in the antagonistic regulation of PcG proteins.
- The discovery of CHD subfamily proteins with trxG-like functions highlights conserved epigenetic mechanisms across higher eukaryotes.
- This research deepens our understanding of the molecular basis of cellular identity maintenance.
Related Concept Videos
01:32Chromatin Modification in iPS Cells
Chromatin modification alters gene expression; therefore, scientists can add histone-modifying enzymes, histone variants, and chromatin remodeling complexes to somatic cells to aid reprogramming into pluripotent stem (iPS) cells.
Compact chromatin makes reprogramming difficult. Enzymes, such as histone demethylases and acetyltransferases, are often added during reprogramming to loosen the chromatin, making the DNA more accessible to transcription factors. Molecules that inhibit histone...
Compact chromatin makes reprogramming difficult. Enzymes, such as histone demethylases and acetyltransferases, are often added during reprogramming to loosen the chromatin, making the DNA more accessible to transcription factors. Molecules that inhibit histone...
02:54Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
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...
02:04Co-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...
02:25Spreading of Chromatin Modifications
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer is an enzyme that can...
Writers
The writer is an enzyme that can...
02:38Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...