ABSTRACT
In this issue of Molecular Cell, Yang and colleagues1 discover age-dependent increases in broad regions of the repressive histone modification H3K27me3. They also demonstrate partial reversion to younger H3K27me3 patterns and gene expression upon resection of older livers.
Subject(s)
Histones , Liver Regeneration , Histones/genetics , Histones/metabolism , Liver Regeneration/genetics , Liver/metabolism , Protein Processing, Post-TranslationalABSTRACT
BACKGROUND: The evolution of multicellularity is a critical event that remains incompletely understood. We use the social amoeba, Dictyostelium discoideum, one of the rare organisms that readily transits back and forth between both unicellular and multicellular stages, to examine the role of epigenetics in regulating multicellularity. RESULTS: While transitioning to multicellular states, patterns of H3K4 methylation and H3K27 acetylation significantly change. By combining transcriptomics, epigenomics, chromatin accessibility, and orthologous gene analyses with other unicellular and multicellular organisms, we identify 52 conserved genes, which are specifically accessible and expressed during multicellular states. We validated that four of these genes, including the H3K27 deacetylase hdaD, are necessary and that an SMC-like gene, smcl1, is sufficient for multicellularity in Dictyostelium. CONCLUSIONS: These results highlight the importance of epigenetics in reorganizing chromatin architecture to facilitate multicellularity in Dictyostelium discoideum and raise exciting possibilities about the role of epigenetics in the evolution of multicellularity more broadly.
