scholarly journals Role of chromatin and Xenopus laevis heat shock transcription factor in regulation of transcription from the X. laevis hsp70 promoter in vivo.

1995 ◽  
Vol 15 (11) ◽  
pp. 6013-6024 ◽  
Author(s):  
N Landsberger ◽  
A P Wolffe
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Xenopus Laevis ◽  
Heat Shock Transcription Factor ◽  
Chromatin Assembly ◽  
Regulation Of Transcription ◽  
Wild Type ◽  
Hsp70 Promoter ◽  
Chromatin Template

Xenopus laevis oocytes activate transcription from the Xenopus hsp70 promoter within a chromatin template in response to heat shock. Expression of exogenous Xenopus heat shock transcription factor 1 (XHSF1) causes the activation of the wild-type hsp70 promoter within chromatin. XHSF1 activates transcription at normal growth temperatures (18 degrees C), but heat shock (34 degrees C) facilitates transcriptional activation. Titration of chromatin in vivo leads to constitutive transcription from the wild-type hsp70 promoter. The Y box elements within the hsp70 promoter facilitate transcription in the presence or absence of chromatin. The presence of the Y box elements prevents the assembly of canonical nucleosomal arrays over the promoter and facilitates transcription. In a mutant hsp70 promoter lacking Y boxes, exogenous XHSF1 activates transcription from a chromatin template much more efficiently under heat shock conditions. Activation of transcription from the mutant promoter by exogenous XHSF1 correlates with the disappearance of a canonical nucleosomal array over the promoter. Chromatin structure on a mutant hsp70 promoter lacking Y boxes can restrict XHSF1 access; however, on both mutant and wild-type promoters, chromatin assembly can also restrict the function of the basal transcriptional machinery. We suggest that chromatin assembly has a physiological role in establishing a transcriptionally repressed state on the Xenopus hsp70 promoter in vivo.

Heat shock-induced interactions of heat shock transcription factor and the human hsp70 promoter examined by in vivo footprinting

1991 ◽  
Vol 11 (1) ◽  
pp. 586-592
Author(s):  
K Abravaya ◽  
B Phillips ◽  
R I Morimoto
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Consensus Sequence ◽  
Regulatory Elements ◽  
Heat Shock Transcription Factor ◽  
Hsp70 Promoter ◽  
Heat Shock Element ◽  
In Vivo Footprinting ◽  
Human Hsp70

Genomic footprinting of the human hsp70 promoter reveals that heat shock induces a rapid binding of a factor, presumably heat shock transcription factor, to a region encompassing five contiguous NGAAN sequences, three perfect and two imperfect matches to the consensus sequence. Arrays of inverted NGAAN sequences have been defined as the heat shock element. No protein is bound to the heat shock element prior to or after recovery from heat shock. Heat shock does not perturb the binding of factors to other regulatory elements in the promoter which contribute to basal expression of the hsp70 gene.

scholarly journals Conserved Region 2.1 of Escherichia coli Heat Shock Transcription Factor σ32 Is Required for Modulating both Metabolic Stability and Transcriptional Activity

2004 ◽  
Vol 186 (22) ◽  
pp. 7474-7480 ◽  
Author(s):  
Mina Horikoshi ◽  
Takashi Yura ◽  
Sachie Tsuchimoto ◽  
Yoshihiro Fukumori ◽  
Masaaki Kanemori
Keyword(s):  
Escherichia Coli ◽  
Transcription Factor ◽  
Heat Shock ◽  
Transcriptional Activity ◽  
Heat Shock Transcription Factor ◽  
Metabolic Stability ◽  
Wild Type ◽  
Shock Proteins ◽  
Insight Into

ABSTRACT Escherichia coli heat shock transcription factor σ32 is rapidly degraded in vivo, with a half-life of about 1 min. A set of proteins that includes the DnaK chaperone team (DnaK, DnaJ, GrpE) and ATP-dependent proteases (FtsH, HslUV, etc.) are involved in degradation of σ32. To gain further insight into the regulation of σ32 stability, we isolated σ32 mutants that were markedly stabilized. Many of the mutants had amino acid substitutions in the N-terminal half (residues 47 to 55) of region 2.1, a region highly conserved among bacterial σ factors. The half-lives ranged from about 2-fold to more than 10-fold longer than that of the wild-type protein. Besides greater stability, the levels of heat shock proteins, such as DnaK and GroEL, increased in cells producing stable σ32. Detailed analysis showed that some stable σ32 mutants have higher transcriptional activity than the wild type. These results indicate that the N-terminal half of region 2.1 is required for modulating both metabolic stability and the activity of σ32. The evidence suggests that σ32 stabilization does not result from an elevated affinity for core RNA polymerase. Region 2.1 may, therefore, be involved in interactions with the proteolytic machinery, including molecular chaperones.

scholarly journals Cooperative binding of heat shock transcription factor to the Hsp70 promoter in vivo and in vitro.

1994 ◽  
Vol 269 (7) ◽  
pp. 4804-4811 ◽  
Author(s):  
J. Amin ◽  
M. Fernandez ◽  
J. Ananthan ◽  
J.T. Lis ◽  
R. Voellmy
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Heat Shock Transcription Factor ◽  
Cooperative Binding ◽  
Hsp70 Promoter

scholarly journals Heat shock-induced interactions of heat shock transcription factor and the human hsp70 promoter examined by in vivo footprinting.

1991 ◽  
Vol 11 (1) ◽  
pp. 586-592 ◽  
Author(s):  
K Abravaya ◽  
B Phillips ◽  
R I Morimoto
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Consensus Sequence ◽  
Regulatory Elements ◽  
Heat Shock Transcription Factor ◽  
Hsp70 Promoter ◽  
Heat Shock Element ◽  
In Vivo Footprinting ◽  
Human Hsp70

Genomic footprinting of the human hsp70 promoter reveals that heat shock induces a rapid binding of a factor, presumably heat shock transcription factor, to a region encompassing five contiguous NGAAN sequences, three perfect and two imperfect matches to the consensus sequence. Arrays of inverted NGAAN sequences have been defined as the heat shock element. No protein is bound to the heat shock element prior to or after recovery from heat shock. Heat shock does not perturb the binding of factors to other regulatory elements in the promoter which contribute to basal expression of the hsp70 gene.

Activation of the heat shock transcription factor by hypoxia in normal and tumor cell lines in vivo and in vitro

1992 ◽  
Vol 23 (4) ◽  
pp. 891-897 ◽  
Author(s):  
Amato J. Giaccia ◽  
Elizabeth A. Auger ◽  
Albert Koong ◽  
David J. Terris ◽  
Andrew I. Minchinton ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Tumor Cell ◽  
Cell Lines ◽  
Heat Shock Transcription Factor ◽  
Tumor Cell Lines

Role of heat shock transcription factor in yeast metallothionein gene expression

1991 ◽  
Vol 11 (7) ◽  
pp. 3676-3681
Author(s):  
W M Yang ◽  
W Gahl ◽  
D Hamer
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Heat Shock ◽  
Gene Transcription ◽  
Heat Shock Factor ◽  
Heat Shock Transcription Factor ◽  
Wild Type ◽  
Promoter Sequences ◽  
Metallothionein Gene ◽  
Upstream Promoter

The induction of Saccharomyces cerevisiae metallothionein gene transcription by Cu and Ag is mediated by the ACE1 transcription factor. In an effort to detect additional stimuli and factors that regulate metallothionein gene transcription, we isolated a Cu-resistant suppressor mutant of an ACE1 deletion strain. Even in the absence of metals, the suppressor mutant exhibited high basal levels of metallothionein gene transcription that required upstream promoter sequences. The suppressor gene was cloned, and its predicted product was shown to correspond to yeast heat shock transcription factor with a single-amino-acid substitution in the DNA-binding domain. The mutant heat shock factor bound strongly to metallothionein gene upstream promoter sequences, whereas wild-type heat shock factor interacted weakly with the same region. Heat treatment led to a slight but reproducible induction of metallothionein gene expression in both wild-type and suppressor strains, and Cd induced transcription in the mutant strain. These studies provide evidence for multiple pathways of metallothionein gene transcriptional regulation in S. cerevisiae.

scholarly journals The DNA-binding activity of the human heat shock transcription factor is regulated in vivo by hsp70.

1993 ◽  
Vol 13 (9) ◽  
pp. 5427-5438 ◽  
Author(s):  
D D Mosser ◽  
J Duchaine ◽  
B Massie
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Dna Binding ◽  
Elevated Temperatures ◽  
Active Role ◽  
Heat Shock Transcription Factor ◽  
Response To Treatment ◽  
Promoter Element ◽  
Heat Shock Promoter

The human heat shock transcription factor (HSF) is maintained in an inactive non-DNA-binding form under nonstress conditions and acquires the ability to bind specifically to the heat shock promoter element in response to elevated temperatures or other conditions that disrupt protein structure. Here we show that constitutive overexpression of the major inducible heat shock protein, hsp70, in transfected human cells reduces the extent of HSF activation after a heat stress. HSF activation was inhibited more strongly in clones that express higher levels of hsp70. These results demonstrate that HSF activity is negatively regulated in vivo by hsp70 and suggest that the cell might sense elevated temperature as a decreased availability of hsp70. HSF activation in response to treatment with sodium arsenite or the proline analog azetidine was also depressed in hsp70-expressing cells relative to that in the nontransfected control cells. As well, the level of activated HSF decreased more rapidly in the hsp70-expressing clones when the cells were heat shocked and returned to 37 degrees C. These results suggest that hsp70 could play an active role in the conversion of HSF back to a conformation that does not bind the heat shock promoter element during the attenuation of the heat shock response.

Absence of heat shock transcription factor 1 retards the regrowth of atrophied soleus muscle in mice

2011 ◽  
Vol 111 (4) ◽  
pp. 1142-1149 ◽  
Author(s):  
Kazuyuki Yasuhara ◽  
Yoshitaka Ohno ◽  
Atsushi Kojima ◽  
Kenji Uehara ◽  
Moroe Beppu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Stress Response ◽  
Heat Shock ◽  
Soleus Muscle ◽  
Heat Shock Transcription Factor ◽  
Hindlimb Suspension ◽  
Wild Type ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Transcription Factor 1

Effects of heat shock transcription factor 1 (HSF1) gene on the regrowth of atrophied mouse soleus muscles were studied. Both HSF1-null and wild-type mice were subjected to continuous hindlimb suspension for 2 wk followed by 4 wk of ambulation recovery. There was no difference in the magnitude of suspension-related decrease of muscle weight, protein content, and the cross-sectional area of muscle fibers between both types of mice. However, the regrowth of atrophied soleus muscle in HSF1-null mice was slower compared with that in wild-type mice. Lower baseline expression level of HSP25, HSC70, and HSP72 were noted in soleus muscle of HSF1-null mice. Unloading-associated downregulation and reloading-associated upregulation of HSP25 and HSP72 mRNA were observed not only in wild-type mice but also in HSF1-null mice. Reloading-associated upregulation of HSP72 and HSP25 during the regrowth of atrophied muscle was observed in wild-type mice. Minor and delayed upregulation of HSP72 at mRNA and protein levels was also seen in HSF1-null mice. Significant upregulations of HSF2 and HSF4 were observed immediately after the suspension in HSF1-null mice, but not in wild-type mice. Therefore, HSP72 expression in soleus muscle might be regulated by the posttranscriptional level, but not by the stress response. Evidence from this study suggested that the upregulation of HSPs induced by HSF1-associated stress response might play, in part, important roles in the mechanical loading (stress)-associated regrowth of skeletal muscle.

scholarly journals Complex Regulation of the Yeast Heat Shock Transcription Factor

2000 ◽  
Vol 11 (5) ◽  
pp. 1739-1751 ◽  
Author(s):  
J. José Bonner ◽  
Tage Carlson ◽  
Donna L. Fackenthal ◽  
David Paddock ◽  
Kimberly Storey ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Conformational Change ◽  
Heat Shock Transcription Factor ◽  
Hsp70 Family ◽  
Ssb Proteins ◽  
Low Glucose ◽  
Complex Regulation ◽  
Surprising Finding

The yeast heat shock transcription factor (HSF) is regulated by posttranslational modification. Heat and superoxide can induce the conformational change associated with the heat shock response. Interaction between HSF and the chaperone hsp70 is also thought to play a role in HSF regulation. Here, we show that the Ssb1/2p member of the hsp70 family can form a stable, ATP-sensitive complex with HSF—a surprising finding because Ssb1/2p is not induced by heat shock. Phosphorylation and the assembly of HSF into larger, ATP-sensitive complexes both occur when HSF activity decreases, whether during adaptation to a raised temperature or during growth at low glucose concentrations. These larger HSF complexes also form during recovery from heat shock. However, if HSF is assembled into ATP-sensitive complexes (during growth at a low glucose concentration), heat shock does not stimulate the dissociation of the complexes. Nor does induction of the conformational change induce their dissociation. Modulation of the in vivo concentrations of the SSA and SSB proteins by deletion or overexpression affects HSF activity in a manner that is consistent with these findings and suggests the model that the SSA and SSB proteins perform distinct roles in the regulation of HSF activity.

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