J Biol Chem, Vol. 275, Issue 12, 9035-9042, March 24, 2000
Comparison of Nucleosome Remodeling by the Yeast Transcription
Factor Pho4 and the Glucocorticoid Receptor*
Florian Then
Bergh
§,
Elizabeth M.
Flinn¶
,
John
Svaren**,
Anthony P.
Wright¶, and
Wolfram
Hörz
From the Institut für Physiologische Chemie,
Universität München,
Schillerstrasse 44, D-80336 München, the ¶ Department of
Biosciences, Karolinska Institute, Novum, S-14157 Huddinge, and
Södertörns Högskola, Box 4101,
S-14104 Huddinge, Sweden
Chromatin reorganization of the PHO5
and murine mammary tumor virus (MMTV) promoters is triggered by binding
of either Pho4 or the glucocorticoid receptor (GR), respectively. In
order to compare the ability of Pho4 and GR to remodel chromatin and
activate transcription, hybrid promoter constructs were created by
insertion of the MMTV B nucleosome sequence into the PHO5
promoter and then transformed into a yeast strain expressing GR.
Activation of either Pho4 (by phosphate depletion) or GR (by hormone
addition) resulted in only slight induction of hybrid promoter
activity. However, simultaneous activation of both Pho4 and GR resulted
in synergistic activation to levels exceeding that of the wild type
PHO5 promoter. Under these conditions, Pho4 completely
disrupted the nucleosome containing its binding site. In contrast, GR
had little effect on the stability of the MMTV B nucleosome. A minimal
transactivation domain of the GR fused to the Pho4 DNA-binding domain
is capable of efficiently disrupting the nucleosome with a Pho4-binding
site, whereas the complementary hybrid protein (Pho4 activation domain, GR DNA-binding domain) does not labilize the B nucleosome. Therefore, we conclude that significant activation by Pho4 requires nucleosome disruption, whereas equivalent transcriptional activation by GR is not
accompanied by overt perturbation of nucleosome structure. Our results
show that the DNA-binding domains of the two factors play critical
roles in determining how chromatin structure is modified during
promoter activation.
*
This work was supported by European Commission Human Capital
and Mobility Network Grant ERBCHRXCT940447, by Deutsche
Forschungsgemeinschaft Grant SFB190, by Fonds der Chemischen Industrie
(to W. H.), by Swedish Cancer Fund Grant 3831-B97-02YBB (to
A. P. W.), and by a NATO Postdoctoral fellowship from the National
Science Foundation (to J. S.).The costs of publication of this
article were defrayed in part by the
payment of page charges. The article
must therefore be hereby marked
"advertisement" in
accordance with 18 U.S.C. Section
1734 solely to indicate this fact.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?