Histone Chaperones
Histone Chaperones - Related Videos
08:16
In Vitro Characterization of Histone Chaperones using Analytical, Pull-Down and Chaperoning Assays
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Cited by 3 •
2021
This protocol describes a battery of methods that includes analytical size-exclusion chromatography to study histone chaperone oligomerization and stability, pull-down assay to unravel histone chaperone-histone interactions, AUC to analyze the stoichiometry of the protein complexes, and histone chaperoning assay to functionally characterize a putative histone chaperone in vitro.
02:32
Histone Modification
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2020
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,...
03:00
Molecular Chaperones and Protein Folding
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2020
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein. The...
02:30
Histone Variants at the Centromere
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2020
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...
02:38
Assessing Bacterial Chaperone Activity via Thermal Unfolding of a Model Protein
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2025
Source: Dahl, J. et al. Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo. J. Vis. Exp. (2016)This video demonstrates a fluorescence spectrophotometer-based assay to evaluate chaperone activity on a substrate protein under acid and heat stress. It outlines the steps for monitoring substrate unfolding and aggregation through light scattering, comparing conditions with and without the chaperone.
FAQs
Their selectivity comes from coordinated protein-protein and protein-DNA interactions. A chaperone captures a newly synthesized or displaced histone, shields its highly charged surfaces, and directs its next interaction rather than allowing uncontrolled contacts. This molecular control reduces inappropriate aggregation and helps ensure that histones are deposited onto, or removed from, DNA in an organized manner.
Free histones can make inappropriate interactions because their charged surfaces readily contact other molecules. Histone chaperones temporarily bind these proteins and shield those surfaces, creating a controlled intermediate for chromatin handling. The same principle applies when histones are displaced from DNA, helping cells manage their redistribution during chromatin assembly or remodeling instead of leaving them uncontrolled.
During assembly, chaperones help guide histones onto DNA so nucleosomes can form in a controlled way. During remodeling, they can support the removal of histones or their repositioning through regulated deposition and release. This ability to assist opposing changes allows chromatin structure to be altered without abandoning control over histone-DNA and histone-protein interactions.
Histone chaperone activity supports genome replication, transcription, and DNA repair because each process requires chromatin to be assembled, altered, or temporarily handled. Their actions also contribute to maintaining epigenetic information, meaning regulatory chromatin-related information that cells preserve as chromatin is managed. Studying these roles connects histone handling with gene expression and genome stability.
Researchers can use histone chaperones to investigate how chromatin is organized and how its structure changes through histone deposition and removal. These studies help connect molecular handling of histones with gene expression, DNA repair, replication, and genome stability. Chaperones therefore provide a way to examine chromatin regulation rather than treating nucleosomes as static structures.
Their relevance follows from the consequences of disturbed chromatin organization. Because histone chaperones help regulate nucleosome formation and remodeling, altered chaperone activity can be examined in relation to disrupted gene expression or genome stability. They also serve as molecular tools for investigating chromatin disruption in disease, helping researchers connect cellular defects with changes in chromatin handling.