H4K20me1 plays a dual role in transcriptional regulation during regeneration and axis patterning ofHydra

Abstract

The evolution of the first body axis in the animal kingdom and an extensive ability to regenerate makes Hydra, a Cnidarian, an excellent model system to understand the underlying epigenetic mechanisms. We identify that SETD8 is critical for regeneration, and H4K20me1 colocalizes with transcriptional activation machinery locally at the β-catenin bound TCF/LEF binding sites on the promoters of head-associated genes, marking an epigenetic activation node. Contrastingly, genome-wide analysis of the H4K20me1 occupancy revealed a negative correlation with transcriptional activation. We propose H4K20me1 as a general repressive histone mark in Cnidaria and describe its dichotomous role in transcriptional regulation in Hydra.

Mono-methylated histones control PARP-1 in chromatin and transcription

“…Rather than disrupting PARP-1 function, we propose that this reduction in H4K20me1 may signify a regulatory shift in chromatin structure, priming these genes for transcriptional activation during heat shock, with PARP-1 playing an independent facilitating role. Moreover, existing studies have highlighted the dual role of H4K20me1, acting as a promoter of transcription elongation in certain contexts and as a repressor in others (13,25,39,40,(42)(43)(44)(45)(46). The elevated enrichment of H4K20me1 in group B genes under normal conditions may indicate a repressive state that requires alleviation for transcriptional activation.…”