Mutational analysis of human heat-shock transcription factor 1 reveals a regulatory role for oligomerization in DNA-binding specificity

2009 ◽  
Vol 424 (2) ◽  
pp. 253-261 ◽  
Author(s):  
Yukiko Takemori ◽  
Yasuaki Enoki ◽  
Noritaka Yamamoto ◽  
Yo Fukai ◽  
Kaori Adachi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Heat Shock ◽  
Dna Binding ◽  
Binding Domain ◽  
Heat Shock Transcription Factor ◽  
Yeast Cells ◽  
Dna Binding Domain ◽  
Regulate Gene Expression ◽  
Regulate Gene

HSF (heat-shock transcription factor) trimers bind to the HSE (heat-shock element) regulatory sequence of target genes and regulate gene expression. A typical HSE consists of at least three contiguous inverted repeats of the 5-bp sequence nGAAn. Yeast HSF is able to recognize discontinuous HSEs that contain gaps in the array of the nGAAn sequence; however, hHSF1 (human HSF1) fails to recognize such sites in vitro, in yeast and in HeLa cells. In the present study, we isolated suppressors of the temperature-sensitive growth defect of hHSF1-expressing yeast cells. Intragenic suppressors contained amino acid substitutions in the DNA-binding domain of hHSF1 that enabled hHSF1 to regulate the transcription of genes containing discontinuous HSEs. The substitutions facilitated hHSF1 oligomerization, suggesting that the DNA-binding domain is important for this conformational change. Furthermore, other oligomerization-prone derivatives of hHSF1 were capable of recognizing discontinuous HSEs. These results suggest that modulation of oligomerization is important for the HSE specificity of hHSF1 and imply that hHSF1 possesses the ability to bind to and regulate gene expression via various types of HSEs in diverse cellular processes.

Solution structure of the DNA-binding domain of Drosophila heat shock transcription factor

1994 ◽  
Vol 1 (9) ◽  
pp. 605-614 ◽  
Author(s):  
Geerten W. Vuister ◽  
Soon-Jong Kim ◽  
András Orosz ◽  
John Marquardt ◽  
Carl Wu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Dna Binding ◽  
Solution Structure ◽  
Binding Domain ◽  
Heat Shock Transcription Factor ◽  
Dna Binding Domain

scholarly journals The Yeast Heat Shock Transcription Factor Changes Conformation in Response to Superoxide and Temperature

2000 ◽  
Vol 11 (5) ◽  
pp. 1753-1764 ◽  
Author(s):  
Sengyong Lee ◽  
Tage Carlson ◽  
Noah Christian ◽  
Kristi Lea ◽  
Jennifer Kedzie ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Dna Binding ◽  
Conformational Change ◽  
Mutational Analysis ◽  
Binding Domain ◽  
Heat Shock Transcription Factor ◽  
Dna Binding Domain ◽  
Yeast Saccharomyces Cerevisiae

In vitro DNA-binding assays demonstrate that the heat shock transcription factor (HSF) from the yeast Saccharomyces cerevisiae can adopt an altered conformation when stressed. This conformation, reflected in a change in electrophoretic mobility, requires that two HSF trimers be bound to DNA. Single trimers do not show this change, which appears to represent an alteration in the cooperative interactions between trimers. HSF isolated from stressed cells displays a higher propensity to adopt this altered conformation. Purified HSF can be stimulated in vitro to undergo the conformational change by elevating the temperature or by exposing HSF to superoxide anion. Mutational analysis maps a region critical for this conformational change to the flexible loop between the minimal DNA-binding domain and the flexible linker that joins the DNA-binding domain to the trimerization domain. The significance of these findings is discussed in the context of the induction of the heat shock response by ischemic stroke, hypoxia, and recovery from anoxia, all known to stimulate the production of superoxide.

scholarly journals Adaptive evolution of transcription factor binding affinities

2017 ◽  
Author(s):  
Jungeui Hong ◽  
Nathan Brandt ◽  
Ally Yang ◽  
Tim Hughes ◽  
David Gresham
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Dna Binding ◽  
Adaptive Evolution ◽  
Consensus Sequence ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Missense Mutations ◽  
Binding Affinities ◽  
Synonymous Mutations

Understanding the molecular basis of gene expression evolution is a central problem in evolutionary biology. However, connecting changes in gene expression to increased fitness, and identifying the functional basis of those changes, remains challenging. To study adaptive evolution of gene expression in real time, we performed long term experimental evolution (LTEE) of Saccharomyces cerevisiae (budding yeast) in ammonium-limited chemostats. Following several hundred generations of continuous selection we found significant divergence of nitrogen-responsive gene expression in lineages with increased fitness. In multiple independent lineages we found repeated selection for non-synonymous mutations in the zinc finger DNA binding domain of the activating transcription factor (TF), GAT1, that operates within incoherent feedforward loops to control expression of the nitrogen catabolite repression (NCR) regulon. Missense mutations in the DNA binding domain of GAT1 reduce its binding affinity for the GATAA consensus sequence in a promoter-specific manner, resulting in increased expression of ammonium permease genes via both direct and indirect effects, thereby conferring increased fitness. We find that altered transcriptional output of the NCR regulon results in antagonistic pleiotropy in alternate environments and that the DNA binding domain of GAT1 is subject to purifying selection in natural populations. Our study shows that adaptive evolution of gene expression can entail tuning expression output by quantitative changes in TF binding affinities while maintaining the overall topology of a gene regulatory network.

GATA-1 interacts with the myeloid PU.1 transcription factor and represses PU.1-dependent transcription

Blood ◽  
2000 ◽  
Vol 95 (8) ◽  
pp. 2543-2551 ◽  
Author(s):  
Claus Nerlov ◽  
Erich Querfurth ◽  
Holger Kulessa ◽  
Thomas Graf
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Dna Binding ◽  
Direct Interaction ◽  
Binding Domain ◽  
Dependent Manner ◽  
Dna Binding Domain ◽  
Transactivation Domain ◽  
Ets Domain ◽  
And Function

Abstract The GATA-1 transcription factor is capable of suppressing the myeloid gene expression program when ectopically expressed in myeloid cells. We examined the ability of GATA-1 to repress the expression and function of the PU.1 transcription factor, a central regulator of myeloid differentiation. We found that GATA-1 is capable of suppressing the myeloid phenotype without interfering with PU.1 gene expression, but instead was capable of inhibiting the activity of the PU.1 protein in a dose-dependent manner. This inhibition was independent of the ability of GATA-1 to bind DNA, suggesting that it is mediated by protein-protein interaction. We examined the ability of PU.1 to interact with GATA-1 and found a direct interaction between the PU.1 ETS domain and the C-terminal finger region of GATA-1. Replacing the PU.1 ETS domain with the GAL4 DNA-binding domain removed the ability of GATA-1 to inhibit PU.1 activity, indicating that the PU.1 DNA-binding domain, rather than the transactivation domain, is the target for GATA-1–mediated repression. We therefore propose that GATA-1 represses myeloid gene expression, at least in part, through its ability to directly interact with the PU.1 ETS domain and thereby interfere with PU.1 function.

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