Conditional silencing: the HMRE mating-type silencer exerts a rapidly reversible position effect on the yeast HSP82 heat shock gene

1993 ◽  
Vol 13 (2) ◽  
pp. 727-738
Author(s):  
S Lee ◽  
D S Gross
Keyword(s):  
Heat Shock ◽  
Mating Type ◽  
Binding Sites ◽  
Position Effect ◽  
Heat Shock Factor ◽  
Heat Shock Gene ◽  
Autonomously Replicating Sequence ◽  
Type Locus ◽  
Factor Binding ◽  
Shock Gene

The HMRE silencer of Saccharomyces cerevisiae has been previously shown to transcriptionally repress class II and class III genes integrated within the HMR silent mating-type locus up to 2.6 kb away. Here we study the ability of this element to repress at an ectopic position, independent of sequences normally associated with it. When integrated 750 bp upstream of the HSP82 heat shock gene, the silencer represses basal-level transcription approximately 5-fold but has no effect on chemical- or heat-shock-induced expression. Such conditional silencing is also seen when the HMRE/HSP82 allele is carried on a centromeric episome or when the entire HMRa domain is transplaced 2.7 kb upstream of HSP82. Notably, the a1 promoter within the immigrant HMRa locus remains fully repressed at the same time HSP82 is derepressed. The position effect mediated by the E silencer is absolutely dependent on the presence of a functional SIR4 gene product, is lost within 1 min following stress induction, and is fully reestablished within 15 min following a return to nonstressful conditions. Similar kinetics of reestablishment are seen in HMRE/HSP82 and HMRa/HSP82 strains, indicating that complete repression can be mediated over thousands of base pairs within minutes. DNase I chromatin mapping reveals that the ABF1, RAP1, and autonomously replicating sequence factor binding sites within the silencer are constitutively occupied in chromatin, unaltered by heat shock or the presence of SIR4. Similarly, the heat shock factor binding site upstream of HSP82 remains occupied under such conditions, suggesting concurrent occupancy of silencer and activator binding sites. Our results are consistent with a model in which silencing at the HMRE/HSP82 allele is mediated by direct or indirect contacts between the silencer protein complex and heat shock factor.

scholarly journals Conditional silencing: the HMRE mating-type silencer exerts a rapidly reversible position effect on the yeast HSP82 heat shock gene.

1993 ◽  
Vol 13 (2) ◽  
pp. 727-738 ◽  
Author(s):  
S Lee ◽  
D S Gross
Keyword(s):  
Heat Shock ◽  
Mating Type ◽  
Binding Sites ◽  
Position Effect ◽  
Heat Shock Factor ◽  
Heat Shock Gene ◽  
Autonomously Replicating Sequence ◽  
Type Locus ◽  
Factor Binding ◽  
Shock Gene

The HMRE silencer of Saccharomyces cerevisiae has been previously shown to transcriptionally repress class II and class III genes integrated within the HMR silent mating-type locus up to 2.6 kb away. Here we study the ability of this element to repress at an ectopic position, independent of sequences normally associated with it. When integrated 750 bp upstream of the HSP82 heat shock gene, the silencer represses basal-level transcription approximately 5-fold but has no effect on chemical- or heat-shock-induced expression. Such conditional silencing is also seen when the HMRE/HSP82 allele is carried on a centromeric episome or when the entire HMRa domain is transplaced 2.7 kb upstream of HSP82. Notably, the a1 promoter within the immigrant HMRa locus remains fully repressed at the same time HSP82 is derepressed. The position effect mediated by the E silencer is absolutely dependent on the presence of a functional SIR4 gene product, is lost within 1 min following stress induction, and is fully reestablished within 15 min following a return to nonstressful conditions. Similar kinetics of reestablishment are seen in HMRE/HSP82 and HMRa/HSP82 strains, indicating that complete repression can be mediated over thousands of base pairs within minutes. DNase I chromatin mapping reveals that the ABF1, RAP1, and autonomously replicating sequence factor binding sites within the silencer are constitutively occupied in chromatin, unaltered by heat shock or the presence of SIR4. Similarly, the heat shock factor binding site upstream of HSP82 remains occupied under such conditions, suggesting concurrent occupancy of silencer and activator binding sites. Our results are consistent with a model in which silencing at the HMRE/HSP82 allele is mediated by direct or indirect contacts between the silencer protein complex and heat shock factor.

scholarly journals Repression of hsp70 heat shock gene transcription by the suppressor of hairy-wing protein of Drosophila melanogaster.

1991 ◽  
Vol 11 (4) ◽  
pp. 1894-1900 ◽  
Author(s):  
C Holdridge ◽  
D Dorsett
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Protein Binding ◽  
Protein Interactions ◽  
Binding Sites ◽  
Zinc Finger Protein ◽  
Gene Promoter ◽  
Heat Shock Gene ◽  
Protein Binding Sites ◽  
Shock Gene

The suppressor of hairy-wing [su(Hw)] locus of Drosophila melanogaster encodes a zinc finger protein that binds a repeated motif in the gypsy retroposon. Mutations of su(Hw) suppress the phenotypes associated with mutations caused by gypsy insertions. To examine the mechanisms by which su(Hw) alters gene expression, a fragment of gypsy containing multiple su(Hw) protein-binding sites was inserted into various locations in the well-characterized Drosophila hsp70 heat shock gene promoter. We found no evidence for activation of basal hsp70 transcription by su(Hw) protein in cultured Drosophila cells but observed that it can repress heat shock-induced transcription. Repression occurred only when su(Hw) protein-binding sites were positioned between binding sites for proteins required for heat shock transcription. We propose that su(Hw) protein interferes nonspecifically with protein-protein interactions required for heat shock transcription, perhaps sterically, or by altering the ability of DNA to bend or twist.

scholarly journals AIRAP, a New Human Heat Shock Gene Regulated by Heat Shock Factor 1

2010 ◽  
Vol 285 (18) ◽  
pp. 13607-13615 ◽  
Author(s):  
Antonio Rossi ◽  
Edoardo Trotta ◽  
Rossella Brandi ◽  
Ivan Arisi ◽  
Marta Coccia ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Factor ◽  
Heat Shock Gene ◽  
Heat Shock Factor 1 ◽  
Shock Gene

scholarly journals Activation of heat shock gene transcription by heat shock factor 1 involves oligomerization, acquisition of DNA-binding activity, and nuclear localization and can occur in the absence of stress.

1993 ◽  
Vol 13 (3) ◽  
pp. 1392-1407 ◽  
Author(s):  
K D Sarge ◽  
S P Murphy ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Dna Binding ◽  
Gene Transcription ◽  
Nuclear Localization ◽  
Heat Shock Factor ◽  
Binding Activity ◽  
Heat Shock Gene ◽  
Dna Binding Activity ◽  
Shock Gene ◽  
In Cells

The existence of multiple heat shock factor (HSF) genes in higher eukaryotes has promoted questions regarding the functions of these HSF family members, especially with respect to the stress response. To address these questions, we have used polyclonal antisera raised against mouse HSF1 and HSF2 to examine the biochemical, physical, and functional properties of these two factors in unstressed and heat-shocked mouse and human cells. We have identified HSF1 as the mediator of stress-induced heat shock gene transcription. HSF1 displays stress-induced DNA-binding activity, oligomerization, and nuclear localization, while HSF2 does not. Also, HSF1 undergoes phosphorylation in cells exposed to heat or cadmium sulfate but not in cells treated with the amino acid analog L-azetidine-2-carboxylic acid, indicating that phosphorylation of HSF1 is not essential for its activation. Interestingly, HSF1 and HSF2 overexpressed in transfected 3T3 cells both display constitutive DNA-binding activity, oligomerization, and transcriptional activity. These results demonstrate that HSF1 can be activated in the absence of physiological stress and also provide support for a model of regulation of HSF1 and HSF2 activity by a titratable negative regulatory factor.

Activation of heat shock gene transcription by heat shock factor 1 involves oligomerization, acquisition of DNA-binding activity, and nuclear localization and can occur in the absence of stress

1993 ◽  
Vol 13 (3) ◽  
pp. 1392-1407
Author(s):  
K D Sarge ◽  
S P Murphy ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Dna Binding ◽  
Gene Transcription ◽  
Nuclear Localization ◽  
Heat Shock Factor ◽  
Binding Activity ◽  
Heat Shock Gene ◽  
Dna Binding Activity ◽  
Shock Gene ◽  
In Cells

The existence of multiple heat shock factor (HSF) genes in higher eukaryotes has promoted questions regarding the functions of these HSF family members, especially with respect to the stress response. To address these questions, we have used polyclonal antisera raised against mouse HSF1 and HSF2 to examine the biochemical, physical, and functional properties of these two factors in unstressed and heat-shocked mouse and human cells. We have identified HSF1 as the mediator of stress-induced heat shock gene transcription. HSF1 displays stress-induced DNA-binding activity, oligomerization, and nuclear localization, while HSF2 does not. Also, HSF1 undergoes phosphorylation in cells exposed to heat or cadmium sulfate but not in cells treated with the amino acid analog L-azetidine-2-carboxylic acid, indicating that phosphorylation of HSF1 is not essential for its activation. Interestingly, HSF1 and HSF2 overexpressed in transfected 3T3 cells both display constitutive DNA-binding activity, oligomerization, and transcriptional activity. These results demonstrate that HSF1 can be activated in the absence of physiological stress and also provide support for a model of regulation of HSF1 and HSF2 activity by a titratable negative regulatory factor.

Sign in / Sign up

Export Citation Format

Share Document