Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (685 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Chromosome regions that are loosely packaged and more accessible to RNA polymerases than heterochromatin. These regions also stain differentially in chromosome banding preparations.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Euchromatins.
Where it fits in the MeSH classification
- Broader topics
- Chromatin
- Narrower topics
- Chromosomal Puffs
Related concepts
- Heterochromatin
- Chromosome Banding
Research landscape
PubMed indexes 878 records tagged with the MeSH heading “Euchromatin” (counts retrieved 2026-10-29). 164 of them (18.7%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 312 records.
Reviews account for 103 records (11.7%) and meta-analyses for 1. Randomized controlled trials number 0 (0.0%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 104 |
| 2000-2009 | 298 |
| 2010-2019 | 312 |
| 2020 onward | 164 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 103 | 11.7% |
| Meta-analyses | 1 | 0.1% |
| Randomized controlled trials | 0 | 0.0% |
Method: PubMed query "Euchromatin"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in genetics and genomics
Genetic findings vary widely in strength. A variant linked to a condition in one study may not replicate in other ancestries, and most common variants have small effects that are meaningful only in aggregate. Studies of rare, high-impact variants can support strong causal claims about a gene, while association studies describe statistical links that need functional and independent replication. Check the sample size, the ancestry of participants, whether results were replicated, and whether a laboratory or clinical outcome was actually measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| A protein complex containing the conserved Swi2/Snf2-related ATPase Swr1p deposits histone variant H2A.Z into euchromatin | 2004 | Research article Design not recorded in structured metadata | 495 | cc by PMID 15045029 · DOI · PMC374244 |
| Mouse Heterochromatin Adopts Digital Compaction States without Showing Hallmarks of HP1-Driven Liquid-Liquid Phase Separation | 2020 | Research article Design not recorded in structured metadata | 270 | cc by PMID 32101700 · DOI · PMC7163299 |
| A-type lamins bind both hetero- and euchromatin, the latter being regulated by lamina-associated polypeptide 2 alpha | 2016 | Research article Design not recorded in structured metadata | 184 | cc by PMID 26798136 · DOI · PMC4817770 |
| Cohesin prevents local mixing of condensed euchromatic domains in living human cells | 2026 | Research article Design not recorded in structured metadata | 6 | cc by PMID 42711428 · DOI · PMC13553310 |
A protein complex containing the conserved Swi2/Snf2-related ATPase Swr1p deposits histone variant H2A.Z into euchromatin [1]
Abstract reading summary — source excerpts
- Opening excerpt
- The conserved histone variant H2A.
- Closing excerpt
- Metazoan orthologs of Swr1p (Drosophila Domino; human SRCAP and p400) may have analogous functions.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (229 words)
The conserved histone variant H2A.Z functions in euchromatin to antagonize the spread of heterochromatin. The mechanism by which histone H2A is replaced by H2A.Z in the nucleosome is unknown. We identified a complex containing 13 different polypeptides associated with a soluble pool of H2A.Z in Saccharomyces cerevisiae. This complex was designated SWR1-Com in reference to the Swr1p subunit, a Swi2/Snf2-paralog. Swr1p and six other subunits were found only in SWR1-Com, whereas six other subunits were also found in the NuA4 histone acetyltransferase and/or the Ino80 chromatin remodeling complex. H2A.Z and SWR1 were essential for viability of cells lacking the EAF1 component of NuA4, pointing to a close functional connection between these two complexes. Strikingly, chromatin immunoprecipitation analysis of cells lacking Swr1p, the presumed ATPase of the complex, revealed a profound defect in the deposition of H2A.Z at euchromatic regions that flank the silent mating type cassette HMR and at 12 other chromosomal sites tested. Consistent with a specialized role for Swr1p in H2A.Z deposition, the majority of the genome-wide transcriptional defects seen in swr1Delta cells were also found in htz1Delta cells. These studies revealed a novel role for a member of the ATP-dependent chromatin remodeling enzyme family in determining the region-specific histone subunit composition of chromatin in vivo and controlling the epigenetic state of chromatin. Metazoan orthologs of Swr1p (Drosophila Domino; human SRCAP and p400) may have analogous functions.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 15045029 · DOI · PMC374244
Mouse Heterochromatin Adopts Digital Compaction States without Showing Hallmarks of HP1-Driven Liquid-Liquid Phase Separation [2]
Abstract reading summary — source excerpts
- Opening excerpt
- The formation of silenced and condensed heterochromatin foci involves enrichment of heterochromatin protein 1 (HP1).
- Closing excerpt
- These findings indicate that heterochromatin foci resemble collapsed polymer globules that are percolated with the same nucleoplasmic liquid as the surrounding euchromatin, which has implications for our understanding of chromatin compartmentalization and its functional consequences.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (144 words)
The formation of silenced and condensed heterochromatin foci involves enrichment of heterochromatin protein 1 (HP1). HP1 can bridge chromatin segments and form liquid droplets, but the biophysical principles underlying heterochromatin compartmentalization in the cell nucleus are elusive. Here, we assess mechanistically relevant features of pericentric heterochromatin compaction in mouse fibroblasts. We find that (1) HP1 has only a weak capacity to form liquid droplets in living cells; (2) the size, global accessibility, and compaction of heterochromatin foci are independent of HP1; (3) heterochromatin foci lack a separated liquid HP1 pool; and (4) heterochromatin compaction can toggle between two "digital" states depending on the presence of a strong transcriptional activator. These findings indicate that heterochromatin foci resemble collapsed polymer globules that are percolated with the same nucleoplasmic liquid as the surrounding euchromatin, which has implications for our understanding of chromatin compartmentalization and its functional consequences.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 32101700 · DOI · PMC7163299
A-type lamins bind both hetero- and euchromatin, the latter being regulated by lamina-associated polypeptide 2 alpha [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs).
- Closing excerpt
- Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (162 words)
Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs). In contrast to lamin B1 being primarily present at the nuclear periphery, lamin A/C also localizes throughout the nucleus, where it associates with the chromatin-binding protein lamina-associated polypeptide (LAP) 2 alpha. Here, we show that lamin A/C also interacts with euchromatin, as determined by chromatin immunoprecipitation of euchromatin- and heterochromatin-enriched samples. By way of contrast, lamin B1 was only found associated with heterochromatin. Euchromatic regions occupied by lamin A/C overlap with those bound by LAP2alpha, and lack of LAP2alpha in LAP2alpha-deficient cells shifts binding of lamin A/C toward more heterochromatic regions. These alterations in lamin A/C-chromatin interactions correlate with changes in epigenetic histone marks in euchromatin but do not significantly affect gene expression. Loss of lamin A/C in heterochromatic regions in LAP2alpha-deficient cells, however, correlated with increased gene expression. Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26798136 · DOI · PMC4817770
Cohesin prevents local mixing of condensed euchromatic domains in living human cells [4]
Abstract reading summary — source excerpts
- Opening excerpt
- The human genome is folded into chromatin loops by the cohesin complex, forming functional chromatin domains that underlie transcription and DNA replication/repair.
- Closing excerpt
- These findings suggest a physical role of cohesin in maintaining the integrity of condensed euchromatic domains and ensuring proper higher-order regulation of gene expression.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
The human genome is folded into chromatin loops by the cohesin complex, forming functional chromatin domains that underlie transcription and DNA replication/repair. However, how cohesin organizes these domains in living cells, especially in active euchromatin, remains elusive. Here, to address this question, we combined single-nucleosome imaging/tracking and super-resolution three-dimensional structured illumination microscopy with euchromatin-specific labeling of histone variant H3.3. Using this nanoscopic approach, we revealed that euchromatin forms condensed domains that are constrained by cohesin-mediated loops. This organization refines the classical view of euchromatin as largely open, in line with emerging evidence. Transcription machinery appears to be located near the condensed domain surfaces/borders. Cohesin loss increased nucleosome-level fluidity within these domains without altering their overall compaction, leading to local mixing of domains and compromising transcriptional insulation. These findings suggest a physical role of cohesin in maintaining the integrity of condensed euchromatic domains and ensuring proper higher-order regulation of gene expression.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42711428 · DOI · PMC13553310
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Programming off and on states in chromatin: mechanisms of Polycomb and trithorax group complexes [5]
- Research article Annotation of the Drosophila melanogaster euchromatic genome: a systematic review [6]
- Research article How to rule the nucleus: divide et impera [7]
- Research article The contradictory definitions of heterochromatin: transcription and silencing [8]
- Research article The heterochromatin protein 1 (HP1) family: put away a bias toward HP1 [9]
- Research article The changing faces of HP1: From heterochromatin formation and gene silencing to euchromatic gene expression: HP1 acts as a positive regulator of transcription [10]
References
- Kobor MS, Venkatasubrahmanyam S, Meneghini MD, Gin JW, Jennings JL, Link AJ, et al.. A protein complex containing the conserved Swi2/Snf2-related ATPase Swr1p deposits histone variant H2A.Z into euchromatin. . 2004. PMID 15045029 · DOI · PMC374244
- Erdel F, Rademacher A, Vlijm R, Tünnermann J, Frank L, Weinmann R, et al.. Mouse Heterochromatin Adopts Digital Compaction States without Showing Hallmarks of HP1-Driven Liquid-Liquid Phase Separation. . 2020. PMID 32101700 · DOI · PMC7163299
- Gesson K, Rescheneder P, Skoruppa MP, von Haeseler A, Dechat T, Foisner R. A-type lamins bind both hetero- and euchromatin, the latter being regulated by lamina-associated polypeptide 2 alpha. . 2016. PMID 26798136 · DOI · PMC4817770
- Shimazoe MA, Iida S, Minami K, Higashi K, Tamura S, Kobayashi Y, et al.. Cohesin prevents local mixing of condensed euchromatic domains in living human cells. . 2026. PMID 42711428 · DOI · PMC13553310
- Simon JA, Tamkun JW. Programming off and on states in chromatin: mechanisms of Polycomb and trithorax group complexes. Curr Opin Genet Dev. 2002. PMID 11893495 · DOI
- Misra S, Crosby MA, Mungall CJ, Matthews BB, Campbell KS, Hradecky P, et al.. Annotation of the Drosophila melanogaster euchromatic genome: a systematic review. Genome Biol. 2002. PMID 12537572 · DOI · PMC151185
- Solovei I, Thanisch K, Feodorova Y. How to rule the nucleus: divide et impera. Curr Opin Cell Biol. 2016. PMID 26938331 · DOI
- Huisinga KL, Brower-Toland B, Elgin SC. The contradictory definitions of heterochromatin: transcription and silencing. Chromosoma. 2006. PMID 16506022 · DOI
- Kwon SH, Workman JL. The heterochromatin protein 1 (HP1) family: put away a bias toward HP1. Mol Cells. 2008. PMID 18664736 · DOI
- Kwon SH, Workman JL. The changing faces of HP1: From heterochromatin formation and gene silencing to euchromatic gene expression: HP1 acts as a positive regulator of transcription. Bioessays. 2011. PMID 21271610 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.