Hydrophobicity of methylated DNA as a possible mechanism for gene silencing.
Phys Biol
; 9(6): 065001, 2012 Dec.
Article
en En
| MEDLINE
| ID: mdl-23196865
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.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
ADN
/
Metilación de ADN
/
Silenciador del Gen
Idioma:
En
Revista:
Phys Biol
Asunto de la revista:
BIOLOGIA
Año:
2012
Tipo del documento:
Article