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Mol. Cell. Biol., Jun 1997, 3284-3294, Vol 17, No. 6
Y Suzuki-Yagawa, M Guermah and RG Roeder
The general transcription initiation factor TFIID contains the TATA-
binding protein (TBP) and TBP-associated factors (TAFs) implicated in the
function of gene-specific activators. Previous studies have indicated that
a hamster cell line (ts13) with a point mutation in the TAF(II)250/CCG1
(TAF(II)250) gene shows temperature-sensitive expression of a subset of
genes and arrests in late G1 at 39.5 degrees C. Here, we report the
identification of cell cycle-specific (G1- specific) genes that appear to
be regulated directly through TAF(II)250 both in vivo and in vitro.
Transcription rates of several cell cycle- regulatory genes were determined
by run-on assays in nuclei from ts13 cells grown at permissive (33 degrees
C) and nonpermissive (39.5 degrees C) temperatures. Temperature-dependent
differences in transcription rates were observed for cyclin A, D1, and D3
genes. In transient-transfection assays, the human cyclin D1 promoter fused
to a luciferase reporter showed a temperature-dependent reduction in
activity in ts13 cells but not in parental BHK cells. In in vitro assays,
upstream sequence-dependent transcription from the human cyclin D1 promoter
was significantly reduced in ts13 nuclear extracts preincubated at 30
degrees C but not in similarly treated BHK nuclear extracts, and
transcription in the ts13 extract was restored by addition of an
affinity-purified human TFIID. Preincubation of the ts13 nuclear extracts
did not affect the function of several GAL4-activation domain fusion
proteins (GAL4-VP16, GAL4-p65, and GAL4-p53) on either the adenovirus major
late or cyclin D1 core promoter bearing GAL4 sites, further indicating that
the effect of the TAF(II)250 mutation is both core promoter and activator
specific.
Copyright © 1997, American Society for Microbiology
The ts13 mutation in the TAF(II)250 subunit (CCG1) of TFIID directly affects transcription of D-type cyclin genes in cells arrested in G1 at the nonpermissive temperature
Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, New York 10021, USA.
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