scholarly journals Neurospora crassa heat shock factor 1 Is an Essential Gene; a Second Heat Shock Factor-Like Gene, hsf2, Is Required for Asexual Spore Formation

2008 ◽  
Vol 7 (9) ◽  
pp. 1573-1581 ◽  
Author(s):  
Seona Thompson ◽  
Nirvana J. Croft ◽  
Antonis Sotiriou ◽  
Hugh D. Piggins ◽  
Susan K. Crosthwaite
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Neurospora Crassa ◽  
Essential Gene ◽  
Expression Profiles ◽  
Heat Shock Factor ◽  
Model Organisms ◽  
Heat Shock Factor 1 ◽  
Wild Type ◽  
Altered Expression

ABSTRACT Appropriate responses of organisms to heat stress are essential for their survival. In eukaryotes, adaptation to high temperatures is mediated by heat shock transcription factors (HSFs). HSFs regulate the expression of heat shock proteins, which function as molecular chaperones assisting in protein folding and stability. In many model organisms a great deal is known about the products of hsf genes. An important exception is the filamentous fungus and model eukaryote Neurospora crassa. Here we show that two Neurospora crassa genes whose protein products share similarity to known HSFs play different biological roles. We report that heat shock factor 1 (hsf1) is an essential gene and that hsf2 is required for asexual development. Conidiation may be blocked in the hsf2 knockout (hsf2 KO ) strain because HSF2 is an integral element of the conidiation pathway or because it affects the availability of protein chaperones. We report that genes expressed during conidiation, for example fluffy, conidiation-10, and repressor of conidiation-1 show wild-type levels of expression in a hsf2 KO strain. However, consistent with the lack of macroconidium development, levels of eas are much reduced. Cultures of the hsf2 KO strain along with two other aconidial strains, the fluffy and aconidial-2 strains, took longer than the wild type to recover from heat shock. Altered expression profiles of hsp90 and a putative hsp90-associated protein in the hsf2 KO strain after exposure to heat shock may in part account for its reduced ability to cope with heat stress.

scholarly journals HSB-1 inhibition and HSF-1 overexpression trigger overlapping transcriptional changes to promote longevity in Caenorhabditis elegans

2019 ◽  
Author(s):  
Surojit Sural ◽  
Tzu-Chiao Lu ◽  
Seung Ah Jung ◽  
Ao-Lin Hsu
Keyword(s):  
Heat Shock ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Heat Shock Factor ◽  
Binding Activity ◽  
Negative Regulator ◽  
Target Sequence ◽  
Heat Shock Factor 1 ◽  
Altered Expression ◽  
Genetic Ablation

ABSTRACTHeat shock factor 1 (HSF-1) is a component of the heat shock response pathway that is induced by cytoplasmic proteotoxic stress. In addition to its role in stress response, HSF-1 also acts as a key regulator of the rate of organismal aging. Overexpression of HSF-1 promotes longevity in C. elegans via mechanisms that remain less understood. Moreover, genetic ablation of a negative regulator of HSF-1, termed as heat shock factor binding protein 1 (HSB-1), results in hsf-1-dependent life span extension in animals. Here we show that in the absence of HSB-1, HSF-1 acquires increased DNA binding activity to its genomic target sequence. Using RNA-Seq to compare the gene expression profiles of the hsb-1 mutant and hsf-1 overexpression strains, we found that while more than 1,500 transcripts show ≥1.5-fold upregulation due to HSF-1 overexpression, HSB-1 inhibition alters the expression of less than 500 genes in C. elegans. Roughly half of the differentially regulated transcripts in the hsb-1 mutant have altered expression also in hsf-1 overexpressing animals, with a strongly correlated fold-expression pattern between the two strains. In addition, genes that are upregulated via both HSB-1 inhibition and HSF-1 overexpression include numerous DAF-16 targets that have known functions in longevity regulation. This study identifies how HSB-1 acts as a specific regulator of the transactivation potential of HSF-1 in non-stressed conditions, thus providing a detailed understanding of the role of HSB-1/HSF-1 signaling pathway in transcriptional regulation and longevity in C. elegans.

Glutamine's protection against cellular injury is dependent on heat shock factor-1

2006 ◽  
Vol 290 (6) ◽  
pp. C1625-C1632 ◽  
Author(s):  
Angela L. Morrison ◽  
Martin Dinges ◽  
Kristen D. Singleton ◽  
Kelli Odoms ◽  
Hector R. Wong ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Factor ◽  
Tetrazolium Salt ◽  
Heat Shock Factor 1 ◽  
Dependent Manner ◽  
Hsp 70 ◽  
Stress Injury ◽  
Cellular Protection ◽  
Dose Dependent

Glutamine (GLN) has been shown to protect cells, tissues, and whole organisms from stress and injury. Enhanced expression of heat shock protein (HSP) has been hypothesized to be responsible for this protection. To date, there are no clear mechanistic data confirming this relationship. This study tested the hypothesis that GLN-mediated activation of the HSP pathway via heat shock factor-1 (HSF-1) is responsible for cellular protection. Wild-type HSF-1 (HSF-1+/+) and knockout (HSF-1−/−) mouse fibroblasts were used in all experiments. Cells were treated with GLN concentrations ranging from 0 to 16 mM and exposed to heat stress injury in a concurrent treatment model. Cell viability was assayed with phenazine methosulfate plus tetrazolium salt, HSP-70, HSP-25, and nuclear HSF-1 expression via Western blot analysis, and HSF-1/heat shock element (HSE) binding via EMSA. GLN significantly attenuated heat-stress induced cell death in HSF-1+/+ cells in a dose-dependent manner; however, the survival benefit of GLN was lost in HSF-1−/− cells. GLN led to a dose-dependent increase in HSP-70 and HSP-25 expression after heat stress. No inducible HSP expression was observed in HSF-1−/− cells. GLN increased unphosphorylated HSF-1 in the nucleus before heat stress. This was accompanied by a GLN-mediated increase in HSF-1/HSE binding and nuclear content of phosphorylated HSF-1 after heat stress. This is the first demonstration that GLN-mediated cellular protection after heat-stress injury is related to HSF-1 expression and cellular capacity to activate an HSP response. Furthermore, the mechanism of GLN-mediated protection against injury appears to involve an increase in nuclear HSF-1 content before stress and increased HSF-1 promoter binding and phosphorylation.

Human heat shock factor 1 is predominantly a nuclear protein before and after heat stress

1999 ◽  
Vol 112 (16) ◽  
pp. 2765-2774 ◽  
Author(s):  
P.A. Mercier ◽  
N.A. Winegarden ◽  
J.T. Westwood
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Nuclear Protein ◽  
Heat Shock Factor ◽  
Nuclear Fraction ◽  
Heat Shock Factor 1 ◽  
Heat Shock Genes ◽  
Before And After ◽  
Biochemical Fractionation ◽  
Multistep Process

The induction of the heat shock genes in eukaryotes by heat and other forms of stress is mediated by a transcription factor known as heat shock factor 1 (HSF1). HSF1 is present in unstressed metazoan cells as a monomer with low affinity for DNA, and upon exposure to stress it is converted to an ‘active’ homotrimer that binds the promoters of heat shock genes with high affinity and induces their transcription. The conversion of HSF1 to its active form is hypothesized to be a multistep process involving physical changes in the HSF1 molecule and the possible translocation of HSF1 from the cytoplasm to the nucleus. While all studies to date have found active HSF1 to be a nuclear protein, there have been conflicting reports on whether the inactive form of HSF is predominantly a cytoplasmic or nuclear protein. In this study, we have made antibodies against human HSF1 and have reexamined its localization in unstressed and heat-shocked human HeLa and A549 cells, and in green monkey Vero cells. Biochemical fractionation of heat-shocked HeLa cells followed by western blot analysis showed that HSF1 was mostly found in the nuclear fraction. In extracts made from unshocked cells, HSF1 was predominantly found in the cytoplasmic fraction using one fractionation procedure, but was distributed approximately equally between the cytoplasmic and nuclear fractions when a different procedure was used. Immunofluorescence microscopy revealed that HSF1 was predominantly a nuclear protein in both heat shocked and unstressed cells. Quantification of HSF1 staining showed that approximately 80% of HSF1 was present in the nucleus both before and after heat stress. These results suggest that HSF1 is predominantly a nuclear protein prior to being exposed to stress, but has low affinity for the nucleus and is easily extracted using most biochemical fractionation procedures. These results also imply that HSF1 translocation is probably not part of the multistep process in HSF1 activation for many cell types.

GLUTAMINE ENHANCES HEAT SHOCK FACTOR-1 NUCLEAR TRANSLOCATION, PHOSHORYLATION AND PROMOTER BINDING FOLLOWING HEAT STRESS INJURY

Shock ◽  
2006 ◽  
Vol 25 (Supplement 1) ◽  
pp. 63
Author(s):  
P. E. Wischmeyer ◽  
A. Morrison ◽  
K. Singleton ◽  
K. Odoms ◽  
H. R. Wong
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Nuclear Translocation ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Stress Injury

scholarly journals Heat stress induces epithelial plasticity and cell migration independent of heat shock factor 1

2012 ◽  
Vol 17 (6) ◽  
pp. 765-778 ◽  
Author(s):  
B. J. Lang ◽  
L. Nguyen ◽  
H. C. Nguyen ◽  
J. L. Vieusseux ◽  
R. C. C. Chai ◽  
...  
Keyword(s):  
Cell Migration ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Epithelial Plasticity

Heat-shock factor 1 both positively and negatively affects cellular clonogenic growth depending on p53 status

2013 ◽  
Vol 452 (2) ◽  
pp. 321-329 ◽  
Author(s):  
Chau H. Nguyen ◽  
Benjamin J. Lang ◽  
Ryan C. C. Chai ◽  
Jessica L. Vieusseux ◽  
Michelle M. Kouspou ◽  
...  
Keyword(s):  
Heat Shock ◽  
Cancer Cell ◽  
Heat Shock Factor ◽  
Mutant P53 ◽  
Heat Shock Factor 1 ◽  
Dependent Manner ◽  
Wild Type ◽  
Clonogenic Growth ◽  
Wild Type P53

HSF1 (heat-shock factor 1) is the master regulator of the heat-shock response; however, it is also activated by cancer-associated stresses and supports cellular transformation and cancer progression. We examined the role of HSF1 in relation to cancer cell clonogenicity, an important attribute of cancer cells. Ectopic expression or HSF1 knockdown demonstrated that HSF1 positively regulated cancer cell clonogenic growth. Furthermore, knockdown of mutant p53 indicated that HSF1 actions were mediated via a mutant p53-dependent mechanism. To examine this relationship more specifically, we ectopically co-expressed mutant p53R273H and HSF1 in the human mammary epithelial cell line MCF10A. Surprisingly, within this cellular context, HSF1 inhibited clonogenicity. However, upon specific knockdown of endogenous wild-type p53, leaving mutant p53R273H expression intact, HSF1 was observed to greatly enhance clonogenic growth of the cells, indicating that HSF1 suppressed clonogenicity via wild-type p53. To confirm this we ectopically expressed HSF1 in non-transformed and H-RasV12-transformed MCF10A cells. As expected, HSF1 significantly reduced clonogenicity, altering wild-type p53 target gene expression levels consistent with a role of HSF1 increasing wild-type p53 activity. In support of this finding, knockdown of wild-type p53 negated the inhibitory effects of HSF1 expression. We thus show that HSF1 can affect clonogenic growth in a p53 context-dependent manner, and can act via both mutant and wild-type p53 to bring about divergent effects upon clonogenicity. These findings have important implications for our understanding of HSF1's divergent roles in cancer cell growth and survival as well as its disparate effect on mutant and wild-type p53.

scholarly journals HSP90 and HSP70 Families in Lateolabrax maculatus: Genome-Wide Identification, Molecular Characterization, and Expression Profiles in Response to Various Environmental Stressors

2021 ◽  
Vol 12 ◽  
Author(s):  
Yalong Sun ◽  
Haishen Wen ◽  
Yuan Tian ◽  
Xuebin Mao ◽  
Xiurong Li ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Environmental Stressors ◽  
Gene Copy ◽  
Heat Shock Factor 1 ◽  
Network Analyses ◽  
Wide Range ◽  
Lateolabrax Maculatus

Heat shock proteins (HSPs) are a large class of highly conserved chaperons, which play important roles in response to elevated temperature and other environmental stressors. In the present study, 5 HSP90 genes and 17 HSP70 genes were systematically characterized in spotted seabass (Lateolabrax maculatus). The evolutionary footprint of HSP genes was revealed via the analysis of phylogeny, chromosome location, and gene copy numbers. In addition, the gene structure features and the putative distribution of heat shock elements (HSEs) and hypoxia response elements (HREs) in the promoter regions were analyzed. The protein-protein interaction (PPI) network analyses results indicated the potential transcriptional regulation between the heat shock factor 1 (HSF1) and HSPs and a wide range of interactions among HSPs. Furthermore, quantitative (q)PCR was performed to detect the expression profiles of HSP90 and HSP70 genes in gill, liver, and muscle tissues after heat stress, meanwhile, the expression patterns in gills under alkalinity and hypoxia stresses were determined by analyzing RNA-Seq datasets. Results showed that after heat stress, most of the examined HSP genes were significantly upregulated in a tissue-specific and time-dependent manners, and hsp90aa1.1, hsp90aa1.2, hsp70.1, and hsp70.2 were the most intense responsive genes in all three tissues. In response to alkalinity stress, 11 out of 13 significantly regulated HSP genes exhibited suppressed expression patterns. Alternatively, among the 12 hypoxia-responsive-expressed HSP genes, 7 genes showed induced expressions, while hsp90aa1.2, hsp70.1, and hsp70.2 had more significant upregulated changes after hypoxic challenge. Our findings provide the essential basis for further functional studies of HSP genes in response to abiotic stresses in spotted seabass.

scholarly journals The interactive association between heat shock factor 1 and heat shock proteins in primary myocardial cells subjected to heat stress

2015 ◽  
Vol 37 (1) ◽  
pp. 56-62 ◽  
Author(s):  
SHU TANG ◽  
HONGBO CHEN ◽  
YANFEN CHENG ◽  
MOHAMMAD ABDEL NASIR ◽  
NICOLE KEMPER ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Myocardial Cells ◽  
Shock Proteins
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