In the context of chromosome folding, it has long been known that chemical modifications of the nucleosomes can alter chromatin fiber folding, as, for example, histone acetylation interferes with folding of nucleosome arrays into compact fibers in vitro (Shahbazian and Grunstein 2007). More complex interactions with chromosome folding are also likely, as modification-specific binding proteins or complexes often have the ability to bind to multiple distinct histone modifications, potentially resulting in bridging interactions between two or more nucleosomes. The integration of chemical modification maps into higher-order chromosome folding studies will be an area of great interest in the near future.
