@article{BeshnovaCherstvyVainshteinetal.2014,
  author    = {Beshnova, Daria A. and Cherstvy, Andrey G. and Vainshtein, Yevhen and Teif, Vladimir B.},
  title     = {Regulation of the nucleosome repeat length in vivo by the DNA sequence, protein concentrations and long-range interactions},
  series = {PLoS Computational Biology : a new community journal},
  volume    = {10},
  journal   = {PLoS Computational Biology : a new community journal},
  number    = {7},
  publisher = {PLoS},
  address   = {San Fransisco},
  issn      = {1553-734X},
  doi       = {10.1371/journal.pcbi.1003698},
  pages     = {14},
  year      = {2014},
  abstract  = {The nucleosome repeat length (NRL) is an integral chromatin property important for its biological functions. Recent experiments revealed several conflicting trends of the NRL dependence on the concentrations of histones and other architectural chromatin proteins, both in vitro and in vivo, but a systematic theoretical description of NRL as a function of DNA sequence and epigenetic determinants is currently lacking. To address this problem, we have performed an integrative biophysical and bioinformatics analysis in species ranging from yeast to frog to mouse where NRL was studied as a function of various parameters. We show that in simple eukaryotes such as yeast, a lower limit for the NRL value exists, determined by internucleosome interactions and remodeler action. For higher eukaryotes, also the upper limit exists since NRL is an increasing but saturating function of the linker histone concentration. Counterintuitively, smaller H1 variants or non-histone architectural proteins can initiate larger effects on the NRL due to entropic reasons. Furthermore, we demonstrate that different regimes of the NRL dependence on histone concentrations exist depending on whether DNA sequence-specific effects dominate over boundary effects or vice versa. We consider several classes of genomic regions with apparently different regimes of the NRL variation. As one extreme, our analysis reveals that the period of oscillations of the nucleosome density around bound RNA polymerase coincides with the period of oscillations of positioning sites of the corresponding DNA sequence. At another extreme, we show that although mouse major satellite repeats intrinsically encode well-defined nucleosome preferences, they have no unique nucleosome arrangement and can undergo a switch between two distinct types of nucleosome positioning.},
  language  = {en}
}
@article{CherstvyTeif2014,
  author    = {Cherstvy, Andrey G. and Teif, Vladimir B.},
  title     = {Electrostatic effect of H1-histone protein binding on nucleosome repeat length},
  series = {Physical biology : a journal for the fundamental understanding of biological systems},
  volume    = {11},
  journal   = {Physical biology : a journal for the fundamental understanding of biological systems},
  number    = {4},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1478-3967},
  doi       = {10.1088/1478-3975/11/4/044001},
  pages     = {6},
  year      = {2014},
  abstract  = {Within a simple biophysical model we describe the effect of electrostatic binding of H1 histone proteins on the nucleosome repeat length in chromatin. The length of wrapped DNA optimizes its binding energy to the histone core and the elastic energy penalty of DNA wrapping. The magnitude of the effect predicted from our model is in agreement with the systematic experimental data on the linear variation of nucleosome repeat lengths with H1/nucleosome ratio (Woodcock C L et al 2006 Chromos. Res. 14 17-25). We compare our model to the data for different cell types and organisms, with a widely varying ratio of bound H1 histones per nucleosome. We underline the importance of this non-specific histone-DNA charge-balance mechanism in regulating the positioning of nucleosomes and the degree of compaction of chromatin fibers in eukaryotic cells.},
  language  = {en}
}