H3K27me1

H3K27me1 refers to the monomethylation of lysine 27 on histone H3, a post-translational modification at a residue that can also carry di- and trimethyl marks. It is part of the broader H3K27 methylation landscape found in chromatin and is detected in various organisms and cell types, with its distribution and function varying by context.

The addition of a single methyl group at H3K27 is carried out by histone methyltransferases associated with Polycomb group–related complexes, and the balance among me1, me2, and me3 states can influence chromatin structure and gene expression. H3K27me3 is the best characterized and is widely linked to transcriptional repression by Polycomb repression complexes; H3K27me1 is less well defined and is thought to participate in context-dependent regulation that may differ from the canonical repressive role of me3. The methylation state at H3K27 is dynamic, and cells can transition between different methylation states in response to developmental cues or environmental signals.

Detection and study methods for H3K27me1 include antibodies specific for the monomethyl form used in chromatin immunoprecipitation (ChIP) assays, as well as mass spectrometry-based approaches. Genome-wide mapping of H3K27me1, in relation to other histone marks, helps illuminate its distribution relative to gene bodies, promoters, and regulatory elements, contributing to understanding of how this mark integrates into epigenetic regulation.

Biological significance attributed to H3K27me1 is context-dependent. In development and differentiation, it is considered part of the dynamic chromatin landscape that coordinates gene expression programs, with effects that can differ between organisms, tissues, and cellular states. Further research continues to clarify the precise roles and mechanisms of H3K27me1 in chromatin regulation.