Table 1.

Current state of understanding of various chromatin structural regulators in the cardiovascular system.

	Studied in CV Development	Studied in CV Disease	Well-studied Players in CV System	Comment
Histone Modifying Enzymes	Extensive	Extensive	HDAC: Class I,II HAT: p300, CBP HMT: PRC2,, MLL HDM: Jumonji domain-containing proteins	Extensive KD/OE and pharmacological studies (105) Limited understanding for genomic distribution of specific modifications and target loci
Histone Variants	Limited	Moderate	H2A.z	Variants expressed in the heart identified (25) but only a few understood mechanistically (26)
Histone Post-translational Modifications	Moderate	Moderate	Acetylation, Methylation	Global positioning analyzed by ChIP-seq (20, 21, 23) Proteomic analyses of PTM abundance, PTM combinations, and PTM interactions with “reader” proteins are still necessary
Non-nucleosomal Structural Proteins	Limited	Moderate	HMGA, HMGB	Some structural proteins have been well-studied in other systems, but their functions have yet to be addressed in the heart (25, 27)
ATP-dependent Chromatin Remodelers	Moderate	Moderate	Brg1, BAF complex	Members of major families studied in the heart (79, 80), though disease studies in this field are still incomplete
DNA Methylation	Moderate	Moderate	meC, Dnmt	Some loci specific studies (106) Few global studies (48)
Noncoding RNA	Extensive	Extensive	miRNAs	Specific miRNAs studied extensively (53, 54) for transcriptional regulation, but the role of noncoding RNA for regulating chromatin structure is needed (60, 61, 107)
Nucleosome Positioning	Limited	Limited	-	Emerging field in chromatin biology not yet explored in the heart
Chromatin Conformation	Limited	Limited	Enhancers and chromatin loops	Studies in the heart of this type are recent and include measuring long-range interactions (89) and nuclear organization by microscopy (108)