Role of histone tails in chromatin folding revealed by a mesoscopic oligonucleosome model

Gaurav Arya, Tamar Schlick

Research output: Contribution to journalArticlepeer-review

Abstract

The role of each histone tail in regulating chromatin structure is elucidated by using a coarse-grained model of an oligonucleosome incorporating flexible histone tails that reproduces the conformational and dynamical properties of chromatin. Specifically, a tailored configurational-bias Monte Carlo method that efficiently samples the possible conformational states of oligonucleosomes yields positional distributions of histone tails around nucleosomes and illuminates the nature of tail/core/DNA interactions at various salt milieus. Analyses indicate that the H4 histone tails are most important in terms of mediating internucleosomal interactions, especially in highly compact chromatin with linker histones, followed by H3, H2A, and H2B tails in decreasing order of importance. In addition to mediating internucleosomal interactions, the H3 histone tails crucially screen the electrostatic repulsion between the entering/exiting DNA linkers. The H2A and H2B tails distribute themselves along the periphery of chromatin fibers and are important for mediating fiber/fiber interactions. A delicate balance between tail-mediated internucleosomal attraction and repulsion among linker DNAs allows the entering/exiting linker DNAs to align perpendicular to each other in linker-histone deficient chromatin, leading to the formation of an irregular zigzag-folded fiber with dominant pair-wise interactions between nucleosomes i and i ± 4.

Original languageEnglish (US)
Pages (from-to)16236-16241
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number44
DOIs
StatePublished - Oct 31 2006

Keywords

  • Chromatin structure regulation
  • DNA/protein complexes
  • Irregular zigzag
  • Monte Carlo simulations
  • Nucleosome

ASJC Scopus subject areas

  • General

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