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Updated: May 16, 2026
09:26
Chromatin Extraction from Frozen Chimeric Liver Tissue for Chromatin Immunoprecipitation Analysis
Published on: March 23, 2021
Chromatin is an ancient innovation conserved between Archaea and Eukarya
Ron Ammar1, Dax Torti, Kyle Tsui
1Department of Molecular Genetics , University of Toronto , Toronto , Canada ; Donnelly Centre , University of Toronto , Toronto , Canada.
Elife
|December 15, 2012
Summary
Histones and chromatin, once thought unique to eukaryotes, are present in archaea. This study maps archaeal nucleosomes, revealing ancient chromatin architecture crucial for gene regulation.
Area of Science:
- Molecular Biology
- Genomics
- Archaeal Biology
Background:
- The eukaryotic nucleosome, composed of a protein octamer and DNA, is vital for DNA compaction and gene expression.
- Chromatin and nucleosomes were traditionally considered exclusive to eukaryotes.
- Archaeal histone homologs forming tetrameric nucleosomes have been identified in some species.
Purpose of the Study:
- To generate the first genome-wide nucleosome occupancy map in an archaeon, Haloferax volcanii.
- To compare nucleosome occupancy with gene expression in Hfx. volcanii.
- To investigate the evolutionary origins of chromatin and its role in gene regulation.
Main Methods:
- Genome-wide nucleosome occupancy mapping in Haloferax volcanii.
- Comprehensive transcriptome analysis of Hfx. volcanii.
- Comparative analysis of archaeal and eukaryotic chromatin structures.
Main Results:
- Archaeal transcripts exhibit eukaryotic chromatin features, including nucleosome-depleted regions at transcriptional start sites.
- Conserved -1 and +1 promoter nucleosomes were identified in archaea.
- Nucleosome occupancy patterns correlate with gene expression levels.
Conclusions:
- Histones and chromatin architecture predate the divergence of Archaea and Eukarya.
- The fundamental role of chromatin in gene expression regulation is ancient.
- Archaeal chromatin organization provides insights into early eukaryotic evolution.
Related Concept Videos
01:01Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
01:01Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
02:05Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
03:17Inheritance of Chromatin Structures
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
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...
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...