Predicting nucleosome positions on the DNA: combining intrinsic sequence preferences and remodeler activities.
Nucleosome positions on the DNA are determined by the intrinsic affinities of histone proteins to a given DNA sequence and by the ATP-dependent activities of chromatin remodeling complexes that can translocate nucleosomes with respect to the DNA. Here, we report a theoretical approach that takes into account both contributions. In the theoretical analysis two types of experiments have been considered: in vitro experiments with a single reconstituted nucleosome and in vivo genome-scale mapping of nucleosome positions. The effect of chromatin remodelers was described by iteratively redistributing the nucleosomes according to certain rules until a new steady state was reached. Three major classes of remodeler activities were identified: (i) the establishment of a regular nucleosome spacing in the vicinity of a strong positioning signal acting as a boundary, (ii) the enrichment/depletion of nucleosomes through amplification of intrinsic DNA-sequence-encoded signals and (iii) the removal of nucleosomes from high-affinity binding sites. From an analysis of data for nucleosome positions in resting and activated human CD4(+) T cells [Schones et al., Cell 132, p. 887] it was concluded that the redistribution of a nucleosome map to a new state is greatly facilitated if the remodeler complex translocates the nucleosome with a preferred directionality.
Teif
Vladimir B
VB
Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum and BioQuant, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. Vladimir.Teif@bioquant.uni-heidelberg.de
Rippe
Karsten
K
D000818:Animals; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000737:chemistry; D004330:Drosophila / Q000235:genetics; D006801:Humans; D009707:Nucleosomes / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D013816:Thermodynamics
D009707:Nucleosomes; D004247:DNA