Chromatin Remodeling
Chromatin Remodeling - Related Videos
10:14
Biochemical Assays for Analyzing Activities of ATP-dependent Chromatin Remodeling Enzymes
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Cited by 4 •
2014
Here we describe biochemical assays that can be used to characterize ATP-dependent chromatin remodeling enzymes for their abilities to 1) catalyze ATP-dependent nucleosome sliding, 2) engage with nucleosome substrates, and 3) hydrolyze ATP in a nucleosome- or DNA-dependent manner.
08:44
Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes
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Cited by 8 •
2014
This protocol describes a procedure for generating and purifying wild type and mutant versions of the human INO80 chromatin remodeling complex. Epitope tagged versions of INO80 subunits are stably expressed in HEK293 cells, and complete complexes and complexes lacking specific sets of subunits are purified by immunoaffinity chromatography.
02:54
Nucleosome Remodeling
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2020
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure. Nucleosome remodeling complex Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
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...
02:21
Chromatin Packaging
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2020
Each human somatic cell contains 6 billion base-pairs of DNA. Each base-pair is 0.34 nm long, which means that each diploid cell contains a staggering 2 meters of DNA. How is such a long DNA strand packed inside a nucleus measuring only 10 - 20 microns in diameter? The chromatin In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
FAQs
ATP hydrolysis provides the energy that specialized remodeling complexes use to alter nucleosome organization. This energy-dependent activity can reposition nucleosomes, remove them, or restructure their arrangement, changing which DNA regions remain physically accessible. As a result, transcription factors and other regulatory proteins can gain or lose opportunities to bind particular genomic regions.
Nucleosome position influences how tightly DNA is packaged around histones and whether regulatory proteins can reach the underlying genetic information. Moving a nucleosome can expose a region for transcription-factor binding, whereas maintaining or creating a more restrictive arrangement can limit access. These changes help cells regulate gene activity without changing the DNA sequence itself.
Remodeling changes the physical accessibility of DNA, which directly influences the binding of transcription factors and other regulatory proteins. When nucleosomes are repositioned, removed, or restructured, previously inaccessible regulatory regions may become available, or accessible regions may become restricted. This provides a mechanism for coordinating gene-control decisions with broader cellular programs.
During cell differentiation, remodeling helps establish distinct gene-expression programs in developing cells. By changing nucleosome organization and DNA accessibility, remodeling complexes can support the regulatory patterns needed for one cell type while limiting access to programs associated with other identities. Studying these changes helps explain how cells maintain specialized functions as they differentiate.
Chromatin remodeling also contributes to DNA replication and DNA repair, where controlled access to packaged genetic material is important. The same capacity to rearrange nucleosomes allows cellular machinery to interact with DNA when it must be copied or corrected. Examining remodeling across these processes shows that its role extends beyond regulating whether genes are expressed.
Disruptions in remodeling complexes can interfere with the gene-expression programs required for normal development and cellular function. Because these complexes also participate in genome organization, transcription, replication, and repair, their malfunction can have broad biological consequences. Research on such disruptions connects molecular changes in chromatin regulation with developmental abnormalities and disease-related mechanisms.