Abstract

AFM images show that chromatin reconstituted on methylated DNA (meDNA) is compacted when imaged under water. Chromatin reconstituted on unmethylated DNA is less compacted and less sensitive to hydration. These differences must reflect changes in the physical properties of DNA on methylation, but prior studies have not revealed large differences between methylated and unmethylated DNA. Quasi-elastic light scattering studies of solutions of methylated and unmethylated DNA support this view. In contrast, AFM images of molecules at a water/solid interface yield a persistence length that nearly doubles (to 92.5 ± 4 nm) when 9% of the total DNA is methylated. This increase in persistence length is accompanied by a decrease in contour length, suggesting that a significant fraction of the meDNA changes into the stiffer A form as the more hydrophobic meDNA is dehydrated at the interface. This suggests a simple mechanism for gene silencing as the stiffer meDNA is more difficult to remove from nucleosomes.

Original languageEnglish (US)
Article number065001
JournalPhysical Biology
Volume9
Issue number6
DOIs
StatePublished - Dec 2012

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Gene Silencing
Hydrophobic and Hydrophilic Interactions
DNA
Chromatin
Water
Nucleosomes
DNA Methylation

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Cell Biology
  • Structural Biology

Cite this

Hydrophobicity of methylated DNA as a possible mechanism for gene silencing. / Kaur, Parminder; Plochberger, Birgit; Costa, Peter; Cope, Stephanie M.; Vaiana, Sara; Lindsay, Stuart.

In: Physical Biology, Vol. 9, No. 6, 065001, 12.2012.

Research output: Contribution to journalArticle

Kaur, Parminder ; Plochberger, Birgit ; Costa, Peter ; Cope, Stephanie M. ; Vaiana, Sara ; Lindsay, Stuart. / Hydrophobicity of methylated DNA as a possible mechanism for gene silencing. In: Physical Biology. 2012 ; Vol. 9, No. 6.
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