2Lomonosov Moscow State University, Biological Faculty, 119991 Moscow, Russia
* To whom correspondence should be addressed.
Received October 19, 2017; Revision received November 27, 2017
It is well known that DNA folding in the eukaryotic cell nucleus is tightly coupled with the operation of epigenetic mechanisms defining the repertoires of the genes expressed in different types of cells. To understand these mechanisms, it is important to know how DNA is packaged in chromatin. About 30 years ago a hypothesis was formulated, according to which epigenetic mechanisms operate not at the level of individual genes, but rather groups of genes localized in structurally and functionally isolated genomic segments that were called structural and functional domains. The question of what exactly these domains constitute has been re-examined multiple times as our knowledge of principles of chromatin folding has changed. In this review, we discuss structural and functional genomic domains in light of the current model of interphase chromosome organization based on the results of analysis of spatial proximity between remote genomic elements.
KEY WORDS: chromatin, cell nucleus, topologically associating domain, Hi-C, noncoding RNA, gene activation