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07:34
A Method to Study de novo Formation of Chromatin Domains
Published on: August 23, 2019
The Drosophila polycomb protein interacts with nucleosomal core particles In vitro via its repression domain
A Breiling1, E Bonte, S Ferrari
1ZMBH, University of Heidelberg, 69120 Heidelberg, Germany.
Molecular and Cellular Biology
|November 24, 1999
Summary
Polycomb (PcG) proteins maintain gene repression by forming higher-order chromatin structures. The Polycomb (PC) protein directly binds nucleosomal core particles, potentially recruiting other PcG proteins to establish these structures.
Area of Science:
- Epigenetics and Gene Regulation
- Chromatin Biology
- Developmental Biology
Background:
- Polycomb group (PcG) proteins are essential for stable and heritable repression of developmental regulator genes.
- PcG proteins are hypothesized to silence genes by forming higher-order chromatin structures, blocking transcriptional machinery access to cis-regulatory elements.
- A key unresolved question is how these higher-order structures anchor to the nucleosomal fiber.
Purpose of the Study:
- To investigate the molecular mechanism by which Polycomb group proteins interact with chromatin at the nucleosomal level.
- To determine if the Polycomb (PC) protein directly interacts with nucleosomal core particles.
- To elucidate the role of PC protein-nucleosome interaction in the establishment of higher-order chromatin structures.
Main Methods:
- In vitro biochemical interaction assays between the Polycomb (PC) protein and nucleosomal core particles.
- Identification of the nucleosome-binding domain within the PC protein.
Main Results:
- Demonstrated a direct biochemical interaction between the Polycomb (PC) protein and nucleosomal core particles in vitro.
- Identified the primary nucleosome-binding domain within the PC protein, which overlaps with its known repression domain.
- Proposed that PC protein binding to nucleosomes serves as a crucial step for recruiting other PcG proteins to chromatin.
Conclusions:
- The Polycomb (PC) protein directly binds to nucleosomal core particles.
- This interaction is mediated by the C-terminal repression domain of the PC protein.
- PC protein binding to nucleosomes is a potential key mechanism for recruiting other PcG proteins, facilitating the formation and regulation of higher-order chromatin structures essential for gene silencing during development.
Related Concept Videos
02:10The 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.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
02:04Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...
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...
02:04Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...
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...
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...