Histone methylation assays detect methyl group additions on lysine and arginine residues, regulating chromatin organization and gene expression. These modifications generate activating or repressive marks depending on residue position and methylation state.
Core Methodologies
- Western blotting: Uses site-specific antibodies to quantify histone methylation levels.
- ELISA: Measures global or targeted methylation from nuclear extracts.
- Chromatin immunoprecipitation (ChIP): Maps methylation patterns across genomic regions.
- Mass spectrometry: Enables precise site-specific and combinatorial modification analysis.
Biological Roles
- Mono-, di-, and tri-methylation states exert distinct regulatory functions.
- H3K4me3 marks active promoters and transcription start sites.
- H3K27me3 mediates repression via Polycomb complexes.
- H3K9me2/3 establishes heterochromatin domains.
- H3K36me3 associates with actively transcribed gene bodies.
Applications
- Cancer research identifies aberrant methylation profiles.
- Developmental biology tracks lineage-specific epigenetic states.
- Drug screening evaluates methyltransferase and demethylase inhibitors.
- Gene regulation studies correlate marks with transcriptional activity.
- Stem cell research monitors differentiation processes.