Chromatin Modification
Chromatin Modification - Related Videos
02:25
Spreading of Chromatin Modifications
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2020
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...
01:32
Chromatin Modification in iPS Cells
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2023
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...
13:20
Chromatin Immunoprecipitation (ChIP) to Assay Dynamic Histone Modification in Activated Gene Expression in Human Cells
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Cited by 11 •
2010
This protocol describes how chromatin immunoprecipitation (ChIP) is used to study the dynamic alterations to the chromatin template that regulate transcription induced by a signal transduction pathway.
08:39
Chromatin Immunoprecipitation
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2023
Histones are proteins that help organize DNA in eukaryotic nuclei by serving as “scaffolds” around which DNA can be wrapped, forming a complex called “chromatin”. These proteins can be modified through the addition of chemical groups, and these changes affect gene expression. Researchers use a technique called chromatin immunoprecipitation (ChIP) to better understand which DNA regions associate with specific histone modifications or other gene regulatory proteins. Antibodies are used to isolate...
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,...
FAQs
Histone acetylation and methylation alter the chemical state of DNA-associated proteins, which can change how nucleosomes are organized. That organization affects whether regulatory regions are accessible to transcription machinery. The important consequence is not a change to the DNA sequence itself, but a change in how the cell presents selected genomic regions for gene-regulatory use.
Histone acetylation and histone methylation act on DNA-associated proteins, whereas DNA methylation acts on DNA itself. All three represent chemical marks that enzymes can add or remove, but they involve different molecular targets. Comparing them helps researchers ask whether altered gene regulation reflects changes in nucleosome organization, DNA-associated proteins, or the DNA molecule.
Developmental signals and environmental conditions can influence the marks placed on chromatin, making gene regulation responsive to cellular context. As these inputs alter nucleosome organization or the accessibility of regulatory regions, cells can use the same DNA sequence in different ways. This responsiveness helps connect external or developmental information with changes in gene-expression patterns.
Distinct cell identities depend on different gene-expression programs, and chromatin modification helps establish and maintain those programs. By shaping access to regulatory regions, the process allows cells with the same underlying DNA to use different portions of their genetic information. This provides a mechanistic link between chromatin state, developmental decisions, and the specialized properties of cells.
Epigenetic inheritance focuses attention on how regulatory states may be established and maintained without altering the underlying DNA sequence. Chromatin modification is central to this question because marks on DNA-associated proteins or DNA can influence the accessibility of regulatory regions over time. Studying these relationships helps explain how gene-regulatory information persists as cells preserve their identities.
Changes in chromatin modification can disrupt gene regulation, making the process relevant to diseases linked to abnormal control of genetic information. The same framework also supports aging research, where investigators examine how regulatory states relate to biological aging. These applications connect molecular changes in chromatin with broader questions about disease mechanisms and age-related changes in gene regulation.