|
||
J. Cell Biol.,
Volume 145, Number 7, June 28, 1999 1341-1354


Analysis of the relationship between transcriptional activators and chromatin organization has
focused largely on lower levels of chromatin structure.
Here we describe striking remodeling of large-scale
chromatin structure induced by a strong transcriptional activator. A VP16-lac repressor fusion protein targeted
the VP16 acidic activation domain to chromosome regions containing lac operator repeats. Targeting was accompanied by increased transcription, localized histone
hyperacetylation, and recruitment of at least three different histone acetyltransferases. Observed effects on large-scale chromatin structure included unfolding of a
90-Mbp heterochromatic chromosome arm into an extended 25-40-µm chromonema fiber, remodeling of
this fiber into a novel subnuclear domain, and propagation of large-scale chromatin unfolding over hundreds of kilobase pairs. These changes in large-scale chromatin structure occurred even with inhibition of ongoing
transcription by
Department of Cell and Structural Biology, and * Program in Biophysics and Computational Biology, University of Illinois,
Urbana-Champaign, Urbana, Illinois 61801
-amanitin. Our results suggest a functional link between recruitment of the transcriptional
machinery and changes in large-scale chromatin structure. Based on the observed long-range propagation of
changes in large-scale chromatin structure, we suggest a
possible rationale for the observed clustering of housekeeping genes within Mbp-sized chromosome bands.
This article has been cited by other articles:
|
|