Condensed chromatin domains in the mammalian nucleus are accessible to large macromolecules.
Most chromatin in interphase nuclei is part of condensed chromatin domains. Previous work has indicated that transcription takes place primarily at the surface of chromatin domains, that is, in the perichromatin region. It is possible that genes inside chromatin domains are silenced due to inaccessibility to macromolecular components of the transcription machinery. We have tested the accessibility of chromatin domains in nuclei of living cells with proteins and dextrans of different molecular sizes. Our results show that chromatin domains are readily accessible to large macromolecules, including proteins with a molecular weight of several hundred kilodaltons. Therefore, the silencing of genes that are incorporated into such domains is not due to the physical inaccessibility of condensed chromatin domains to transcription factors.
Verschure
Pernette J
PJ
Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands. pj.verschure@science.uva.nl
van der Kraan
Ineke
I
Manders
Erik M M
EM
Hoogstraten
Deborah
D
Houtsmuller
Adriaan B
AB
van Driel
Roel
R
D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D003911:Dextrans / Q000378:metabolism*; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D002843:Chromatin; D003911:Dextrans; D011993:Recombinant Fusion Proteins