Structural Basis of Nucleosome Recognition and Modulation.

Chromatin structure and dynamics regulate key cellular processes such as DNA replication, transcription, repair, remodeling, and gene expression, wherein different protein factors interact with the nucleosomes. In these events, DNA and RNA polymerases, chromatin remodeling enzymes and transcription factors interact with nucleosomes, either in a DNA-sequence-specific manner and/or by recognizing different structural features on the nucleosome. The molecular details of the recognition of a nucleosome by different viral proteins, remodeling enzymes, histone post-translational modifiers, and RNA polymerase II, have been explored in the recent past. The present review puts forth critical insights into the basic mechanisms of nucleosome recognition by the various protein factors and the role of distinct surface epitopes on a nucleosome. These determinants of the underlying specificity include features such as the acidic patch, arginine anchor, histone post-translational modifications, core DNA, DNA lesions, and linker DNA.