The linker-protein network: control of nucleosomal DNA accessibility.
Numerous studies have recently addressed the accessibility of nucleosomal DNA to protein factors. Two popular concepts - the histone code and chromatin remodeling - consider the nucleosome as a passive entity that 'waits' to be marked by histone modifications and is 'mobilized' by ATP-dependent remodelers. Here, we propose a holistic view of the nucleosome as an active, dynamic entity, the accessibility of which is controlled by binding of different linker proteins to the DNA entry/exit site. The linker proteins might directly compete for this binding site; alternatively, protein chaperones and/or chromatin remodelers might exchange one linker protein for another. Finally, according to our proposed model, the exchange factors are themselves controlled by post-translational modifications or binding of protein partners, to respond to the ever-changing intra- and extra-cellular environment.
Zlatanova
Jordanka
J
Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA. jordanka@uwyo.edu
Seebart
Corrine
C
Tomschik
Miroslav
M
D000818:Animals; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D004247:DNA / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D018832:Molecular Chaperones / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000502:physiology*
D006657:Histones; D018832:Molecular Chaperones; D009707:Nucleosomes; D004247:DNA