Related Experiment Video
Updated: Jul 5, 2026
10:54
Extraction of Histones from Clinical Specimens for Epigenetic Profiling by Mass Spectrometry
Published on: November 21, 2025
Sequence-specific histone methylation is detectable on circulating nucleosomes in plasma.
Ugur Deligezer1, Ebru E Akisik, Nilgün Erten
1Department of Basic Oncology, Oncology Institute, Istanbul University, Istanbul, Turkey.
Clinical Chemistry
|May 20, 2008
Summary
Histone methylation, specifically H3K9me1, is detectable in plasma, differing between mono- and oligonucleosomes. This finding may enable future cancer diagnostics via circulating histone modifications.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- DNA methylation and histone modifications are implicated in cancer.
- While tumor DNA methylation is detectable in serum, histone modifications in circulation are unstudied.
- This study investigates histone methylation, specifically H3K9me1, in plasma.
Purpose of the Study:
- To determine if histone methylation (H3K9me1) is detectable in plasma.
- To investigate sequence-dependent detection of H3K9me1 on mono- and oligonucleosomes.
- To compare H3K9me1 levels on repetitive ALU elements versus a single-copy gene (CDKN2A).
Main Methods:
- 21 multiple myeloma patients were enrolled.
- ELISA and real-time PCR assessed free nucleosomes and cell-free DNA in plasma.
- Chromatin immunoprecipitation analyzed H3K9me1 presence and concentration.
Main Results:
- Free nucleosomes and DNA were detected in plasma, correlating quantitatively.
- H3K9me1 detection on free nucleosomes was sequence-dependent.
- H3K9me1 concentrations differed significantly between mono- and oligonucleosomes (P=0.004).
- H3K9me1 was detected at higher rates and concentrations on ALU elements compared to CDKN2A promoter (P<0.001).
Conclusions:
- Histone methylation (H3K9me1) is detectable in circulating plasma.
- Plasma H3K9me1 levels differ based on nucleosome size and DNA sequence.
- These findings may form a basis for detecting cancer-specific histone modifications in circulation.
Related Concept Videos
02:32Histone Modification
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,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
02:25Spreading of Chromatin Modifications
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...
Writers
The writer is an enzyme that can...