Epigenetic engineering reveals a balance between histone modifications and transcription in kinetochore maintenance.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27841270.
- Also identified by DOI 10.1038/ncomms13334 and PMC identifier 5114538.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Centromeres consist of specialized centrochromatin containing CENP-A nucleosomes intermingled with H3 nucleosomes carrying transcription-associated modifications. We have designed a novel synthetic biology 'in situ epistasis' analysis in which H3 dimethylated on lysine 4 (H3K4me2) demethylase LSD2 plus synthetic modules with competing activities are simultaneously targeted to a synthetic alphoid<sup>tetO</sup> HAC centromere. This allows us to uncouple transcription from histone modifications at the centromere. Here, we report that H3K4me2 loss decreases centromeric transcription, CENP-A assembly and stability and causes spreading of H3K9me3 across the HAC, ultimately inactivating the centromere. Surprisingly, CENP-28/Eaf6-induced transcription of the alphoid<sup>tetO</sup> array associated with H4K12 acetylation does not rescue the phenotype, whereas p65-induced transcription associated with H3K9 acetylation does rescue. Thus mitotic transcription plus histone modifications including H3K9ac constitute the 'epigenetic landscape' allowing CENP-A assembly and centrochromatin maintenance. H3K4me2 is required for the transcription and H3K9ac may form a barrier to prevent heterochromatin spreading and kinetochore inactivation at human centromeres.
Medical subject headings
- Epigenesis, Genetic
- Histone Code
- Kinetochores
- Transcription, Genetic