| 636 |
Histone
acetylation increases chromatin accessibility |
Sabine
M. Görisch, Malte Wachsmuth, Katalin Fejes Tóth, Peter Lichter and Karsten Rippe |
Heterochromatin,
Image correlation spectroscopy,
Trichostatin A, Microinjection |
HeLa cells (ATCC: CCL-2) were
cultured on glass coverslips for fixed cell analysis and on MatTek glass bottom dishes (MatTek,
Ashland, MA) for in vivo imaging in DMEM for 1 day.
|
confocal
laser scanning fluorescence microscopy |
|
|
HeLa |
| |
In eukaryotes, the interaction of DNA
with proteins and supramolecular complexes involved in gene expression is controlled by the
dynamic organization of chromatin inasmuch as it defines the DNA accessibility. Here, the nuclear
distribution of microinjected fluorescein-labeled dextrans of 42 kDa to 2.5 MDa molecular mass
was used to characterize the chromatin accessibility in dependence on histone acetylation. Measurements
of the fluoresceindextran sizes were combined with an image correlation spectroscopy analysis,
and three different interphase chromatin condensation states with apparent pore sizes of 16-20
nm, 36-56 nm and 60-100 nm were identified. A reversible change of the chromatin conformation
to a uniform 60-100 nm pore size distribution was observed upon increased histone acetylation.
This result identifies histone acetylation as a central factor in the dynamic regulation of
chromatin accessibility during interphase. In mitotic chromosomes, the chromatin exclusion limit
was 10-20 nm and independent of the histone acetylation state. |
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