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Assembly of Nucleosomal Arrays from Recombinant Core Histones and Nucleosome Positioning DNA
Published on: September 10, 2013
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Phylogenomics of the nucleosome
Harmit S Malik1, Steven Henikoff
1Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
Nature Structural Biology
|October 30, 2003
Summary
Histones, crucial for packaging DNA, are not static. Variant histones (H2A, H3) have evolved diverse functions beyond simple genome compaction, challenging traditional views.
Area of Science:
- Molecular Biology
- Genetics
- Evolutionary Biology
Background:
- Histones are core structural proteins in eukaryotic DNA packaging, forming nucleosomes.
- Traditionally considered slow-evolving scaffold proteins, recent findings suggest histone diversification.
Purpose of the Study:
- To explore the functional diversification of histone variants.
- To investigate the evolutionary origins of diverse histone functions.
Main Methods:
- Phylogenetic analysis of histone gene sequences.
- Comparative genomics of histone variant evolution.
Main Results:
- Histone H2A and H3 variants have evolved specialized roles.
- These roles include epigenetic silencing, gene expression regulation, and centromere function.
- Histone evolution contradicts the notion of monotonous genome packaging proteins.
Conclusions:
- Histone variants exhibit significant functional and evolutionary diversification.
- Phylogenetic approaches are key to understanding the evolution of these diverse histone functions.
Related Concept Videos
02:33The Nucleosome
DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
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Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
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02:54Nucleosome Remodeling
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DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
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DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
01:19The Nucleosome
Human DNA is almost two meters long. However, it is compressed inside a tiny nucleus measuring only a few microns in diameter. To make this degree of compaction possible, DNA is organized into several sequential levels so that it can fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
01:12The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
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