Characterization of orange-spotted grouper (Epinephelus coioides) interferon regulatory factor 4 regulated by heat shock factor 1 during heat stress in response to antiviral immunity

2020 ◽  
Vol 106 ◽  
pp. 755-767
Author(s):  
Chai Foong Lai ◽  
Ting-Yu Wang ◽  
Min-I Yeh ◽  
Tzong-Yueh Chen
2006 ◽  
Vol 290 (6) ◽  
pp. C1625-C1632 ◽  
Author(s):  
Angela L. Morrison ◽  
Martin Dinges ◽  
Kristen D. Singleton ◽  
Kelli Odoms ◽  
Hector R. Wong ◽  
...  

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.


1999 ◽  
Vol 112 (16) ◽  
pp. 2765-2774 ◽  
Author(s):  
P.A. Mercier ◽  
N.A. Winegarden ◽  
J.T. Westwood

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.


2008 ◽  
Vol 7 (9) ◽  
pp. 1573-1581 ◽  
Author(s):  
Seona Thompson ◽  
Nirvana J. Croft ◽  
Antonis Sotiriou ◽  
Hugh D. Piggins ◽  
Susan K. Crosthwaite

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.


Shock ◽  
2006 ◽  
Vol 25 (Supplement 1) ◽  
pp. 63
Author(s):  
P. E. Wischmeyer ◽  
A. Morrison ◽  
K. Singleton ◽  
K. Odoms ◽  
H. R. Wong

2009 ◽  
Vol 166 (15) ◽  
pp. 1646-1659 ◽  
Author(s):  
Ramesha A. Reddy ◽  
Bhumesh Kumar ◽  
Palakolanu Sudhakar Reddy ◽  
Rabi N. Mishra ◽  
Srikrishna Mahanty ◽  
...  

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