Chromatin Digestion
Chromatin Digestion - Related Videos
04:57
Chromatin Shearing: A Method to Generate Chromatin Fragments Using Enzymatic Digestion
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2023
This video describes the protocol for chromatin shearing using micrococcal nuclease enzymatic digestion. Chromatin shearing is an essential step in Chromatin immunoprecipitation or ChIp workflow, which helps investigate protein-DNA interaction in human chronic myeloid leukemia cells. In the feature protocol chromatin shearing is performed using sonication.
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.
07:03
Native Chromatin Immunoprecipitation of Neurosphere Cells
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2025
Source: Mendez, F. M. et al., Native Chromatin Immunoprecipitation Using Murine Brain Tumor Neurospheres. J. Vis. Exp. (2018).This video demonstrates the isolation of protein-DNA complexes from neurosphere cells derived from a mouse brain tumor using native chromatin immunoprecipitation. It details the steps for chromatin preparation, immunoprecipitation, washing, and protein digestion to release DNA for downstream analysis.
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...
FAQs
Micrococcal nuclease preferentially cleaves linker DNA because that DNA lies relatively exposed between nucleosomes, whereas histone-associated DNA is comparatively protected. This selective sensitivity makes the resulting fragment pattern informative rather than random. By examining which chromatin-associated regions resist cleavage and which are fragmented, researchers infer how histones partition DNA into protected and accessible segments.
Digestion conditions determine how much chromatin is fragmented and therefore affect which structural features remain visible. Controlled digestion preserves a relationship between nuclease cleavage and chromatin organization, while the resulting fragment population can be examined for patterns associated with nucleosome arrangement. Fragment distribution reflects both the extent of cleavage and the degree of protection provided by histones.
Protected DNA fragments provide evidence that histones shield particular DNA segments from nuclease access. Comparing protected material with DNA from more exposed linker regions helps distinguish packaging effects within chromatin. This information supports studies of nucleosome positioning and chromatin accessibility because it connects physical protection patterns with the organization of DNA around histone proteins.
Fragment analysis can indicate which DNA segments remain associated with protective proteins during nuclease treatment. In chromatin, histones are the explicitly described protective proteins, so resistance patterns provide evidence about DNA-protein interactions and DNA packaging. This focus helps researchers investigate how protein-associated protection contributes to chromatin structure alongside nucleosome positioning and accessibility.
A typical assay exposes chromatin to a nuclease such as micrococcal nuclease under controlled digestion conditions. The enzyme fragments relatively exposed linker DNA, leaving histone-protected regions comparatively intact. Researchers then analyze the resulting DNA fragments. This workflow converts differences in chromatin protection into measurable fragment patterns that can be interpreted in relation to chromatin structure.
Researchers examine the fragment pattern produced after nuclease treatment to identify how DNA is partitioned into nucleosome-associated and linker regions. Because cleavage favors exposed linker DNA, the retained or generated fragments provide evidence about where nucleosomes are positioned along chromatin. This application helps investigate genome organization at the level of DNA packaging rather than transcriptional activity alone.
In biology, the technique provides a physical view of processes often studied through gene expression. Fragment patterns reveal chromatin accessibility and histone protection, which can be considered alongside transcriptional activity. This makes chromatin digestion useful for connecting DNA packaging with gene regulation, genome organization, epigenetic states, and broader effects on cellular function.