Chromatin domains and the interchromatin compartment form structurally defined and functionally interacting nuclear networks.
In spite of strong evidence that the nucleus is a highly organized organelle, a consensus on basic principles of the global nuclear architecture has not so far been achieved. The chromosome territory-interchromatin compartment (CT-IC) model postulates an IC which expands between chromatin domains both in the interior and the periphery of CT. Other models, however, dispute the existence of the IC and claim that numerous chromatin loops expand between and within CTs. The present study was undertaken to resolve these conflicting views. (1) We demonstrate that most chromatin exists in the form of higher-order chromatin domains with a compaction level at least 10 times above the level of extended 30 nm chromatin fibers. A similar compaction level was obtained in a detailed analysis of a particularly gene-dense chromosome region on HSA 11, which often expanded from its CT as a finger-like chromatin protrusion. (2) We further applied an approach which allows the experimental manipulation of both chromatin condensation and the width of IC channels in a fully reversible manner. These experiments, together with electron microscopic observations, demonstrate the existence of the IC as a dynamic, structurally distinct nuclear compartment, which is functionally linked with the chromatin compartment.
Albiez
Heiner
H
Department of Biology II, LMU Biozentrum, Grosshaderner Strasse 2, 82152, Planegg-Martinsried, Germany.
Cremer
Marion
M
Tiberi
Cinzia
C
Vecchio
Lorella
L
Schermelleh
Lothar
L
Dittrich
Sandra
S
Küpper
Katrin
K
Joffe
Boris
B
Thormeyer
Tobias
T
von Hase
Johann
J
Yang
Siwei
S
Rohr
Karl
K
Leonhardt
Heinrich
H
Solovei
Irina
I
Cremer
Christoph
C
Fakan
Stanislav
S
Cremer
Thomas
T
D000818:Animals; D016466:CHO Cells; D002463:Cell Membrane Permeability; D002467:Cell Nucleus / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure*; D002875:Chromosomes / Q000648:ultrastructure; D006224:Cricetinae; D004247:DNA / Q000096:biosynthesis; D006367:HeLa Cells; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008957:Models, Genetic; D012313:RNA / Q000096:biosynthesis; D012319:RNA Polymerase II / Q000378:metabolism
D002843:Chromatin; D012313:RNA; D004247:DNA; D012319:RNA Polymerase II