Tissue development requires the coordinated action of transcriptional mediators and chromatin modifiers enabling progenitor cell lineage transition and differentiation. Protein posttranslational modifications, such as acetylation and methylation, acts to fine-tune lineage effectors and epigenetic modifiers by affecting target protein properties. Citrullination, the enzymatic posttranslational conversion of the amino acid arginine to citrulline, act interdependently with other more established posttranslational modifications on histone tails to directly restrict or facilitate gene transcription or by modifying chromatin accessibility.