scholarly journals Recovery from heat shock requires the microRNA pathway in Caenorhabditis elegans

PLoS Genetics ◽  
2021 ◽  
Vol 17 (8) ◽  
pp. e1009734
Author(s):  
Delaney C. Pagliuso ◽  
Devavrat M. Bodas ◽  
Amy E. Pasquinelli
Keyword(s):  
Caenorhabditis Elegans ◽  
Heat Shock ◽  
Transcriptional Activation ◽  
Mirna Regulation ◽  
Hsp 70 ◽  
Rapid Induction ◽  
Target Sites ◽  
Mirna Pathway ◽  
Shock Proteins ◽  
Microrna Pathway

The heat shock response (HSR) is a highly conserved cellular process that promotes survival during stress. A hallmark of the HSR is the rapid induction of heat shock proteins (HSPs), such as HSP-70, by transcriptional activation. Once the stress is alleviated, HSPs return to near basal levels through incompletely understood mechanisms. Here, we show that the microRNA pathway acts during heat shock recovery in Caenorhabditis elegans. Depletion of the miRNA Argonaute, Argonaute Like Gene 1 (ALG-1), after an episode of heat shock resulted in decreased survival and perdurance of high hsp-70 levels. We present evidence that regulation of hsp-70 is dependent on miR-85 and sequences in the hsp-70 3’UTR that contain target sites for this miRNA. Regulation of hsp-70 by the miRNA pathway was found to be particularly important during recovery from HS, as animals that lacked miR-85 or its target sites in the hsp-70 3’UTR overexpressed HSP-70 and exhibited reduced viability. In summary, our findings show that down-regulation of hsp-70 by miR-85 after HS promotes survival, highlighting a previously unappreciated role for the miRNA pathway during recovery from stress.

Progesterone enhances target gene transcription by receptor free of heat shock proteins hsp90, hsp56, and hsp70

1991 ◽  
Vol 11 (10) ◽  
pp. 4998-5004
Author(s):  
M K Bagchi ◽  
S Y Tsai ◽  
M J Tsai ◽  
B W O'Malley
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Protein ◽  
Transcriptional Activation ◽  
Target Gene ◽  
Steroid Hormone ◽  
Receptor Activation ◽  
Target Cells ◽  
Dependent Manner ◽  
Shock Proteins

Steroid receptors regulate transcription of target genes in vivo and in vitro in a steroid hormone-dependent manner. Unoccupied progesterone receptor exists in the low-salt homogenates of target cells as a functionally inactive 8 to 10S complex with several nonreceptor components such as two molecules of 90-kDa heat shock protein (hsp90), a 70-kDa heat shock protein (hsp70), and a 56-kDa heat shock protein (hsp56). Ligand-induced dissociation of receptor-associated proteins such as hsp90 has been proposed as the mechanism of receptor activation. Nevertheless, it has not been established whether, beyond release of heat shock proteins, the steroidal ligand plays a role in modulating receptor activity. To examine whether the release of these nonreceptor proteins from receptor complex results in a constitutively active receptor, we isolated an unliganded receptor form essentially free of hsp90, hsp70, and hsp56. Using a recently developed steroid hormone-responsive cell-free transcription system, we demonstrate for the first time that the dissociation of heat shock proteins is not sufficient to generate a functionally active receptor. This purified receptor still requires hormone for high-affinity binding to a progesterone response element and for efficient transcriptional activation of a target gene. When an antiprogestin, Ru486, is bound to the receptor, it fails to promote efficient transcription. We propose that in the cell, in addition to the release of receptor-associated inhibitory proteins, a distinct hormone-mediated activation event must precede efficient gene activation.

Morphological and molecular modifications induced by heat shock in Drosophila melanogaster embryos

Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 167-182
Author(s):  
Giorgio Graziosi ◽  
Franco de Cristini ◽  
Angelo di Marcotullio ◽  
Roberto Marzari ◽  
Fulvio Micali ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Dna Synthesis ◽  
Histological Analysis ◽  
Developmental Stages ◽  
Early Embryo ◽  
Direct Relation ◽  
Hsp 70 ◽  
Survival Pattern ◽  
Shock Proteins

The early embryo of Drosophila melanogaster did not survive treatment at 37 °C (heat shock) for 25 min. The histological analysis of eggs treated in this way showed that the heat shock caused disintegration of nuclei and of cytoplasmic islands, displacement and swelling of nuclei and blocked mitoses. These effects were not observed in embryos treatedafter blastoderm formation. After this stage, we noticed that development was slowed down. The heat shock proteins (hsp 83,70 and 68) were, under shock, synthesized at all developmental stages. There was little or no synthesis of hsp 70 and 68 in unfertilized eggs, but synthesis increased in proportion to the number of nuclei present. Most probably, hsp 70 synthesis was directed by zygotic mRNA. DNA synthesis was not blocked by the heat shock though the overall incorporation of [3H]thymidine was substantially reduced, presumably because of the block of mitoses. We did not find a direct relation between survival pattern and hsp synthesis. We concluded that some, at least, of the heat shock genes can be activated at all developmental stages and that heat shock could be used for synchronizing mitoses.

scholarly journals The noncanonical small heat shock protein HSP-17 from Caenorhabditis elegans is a selective protein aggregase

2020 ◽  
Vol 295 (10) ◽  
pp. 3064-3079 ◽  
Author(s):  
Manuel Iburg ◽  
Dmytro Puchkov ◽  
Irving U. Rosas-Brugada ◽  
Linda Bergemann ◽  
Ulrike Rieprecht ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Heat Shock ◽  
Small Heat Shock Protein ◽  
Independent Manner ◽  
C Elegans ◽  
Higher Eukaryotes ◽  
Prolonged Heat ◽  
Shock Proteins ◽  
Excretory Organs

Small heat shock proteins (sHsps) are conserved, ubiquitous members of the proteostasis network. Canonically, they act as “holdases” and buffer unfolded or misfolded proteins against aggregation in an ATP-independent manner. Whereas bacteria and yeast each have only two sHsps in their genomes, this number is higher in metazoan genomes, suggesting a spatiotemporal and functional specialization in higher eukaryotes. Here, using recombinantly expressed and purified proteins, static light-scattering analysis, and disaggregation assays, we report that the noncanonical sHsp HSP-17 of Caenorhabditis elegans facilitates aggregation of model substrates, such as malate dehydrogenase (MDH), and inhibits disaggregation of luciferase in vitro. Experiments with fluorescently tagged HSP-17 under the control of its endogenous promoter revealed that HSP-17 is expressed in the digestive and excretory organs, where its overexpression promotes the aggregation of polyQ proteins and of the endogenous kinase KIN-19. Systemic depletion of hsp-17 shortens C. elegans lifespan and severely reduces fecundity and survival upon prolonged heat stress. HSP-17 is an abundant protein exhibiting opposing chaperone activities on different substrates, indicating that it is a selective protein aggregase with physiological roles in development, digestion, and osmoregulation.

scholarly journals Species-specific collaboration of heat shock proteins (Hsp) 70 and 100 in thermotolerance and protein disaggregation

2011 ◽  
Vol 108 (17) ◽  
pp. 6915-6920 ◽  
Author(s):  
M. Miot ◽  
M. Reidy ◽  
S. M. Doyle ◽  
J. R. Hoskins ◽  
D. M. Johnston ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Hsp 70 ◽  
Species Specific ◽  
Shock Proteins

Expression of heat shock genes of Neurospora crassa: effect of hyperthermia and other stresses on mRNA levels

1988 ◽  
Vol 66 (2) ◽  
pp. 81-92 ◽  
Author(s):  
Carol A. Curle ◽  
M. Kapoor
Keyword(s):  
Heat Shock ◽  
Neurospora Crassa ◽  
Sodium Arsenite ◽  
Gene Probe ◽  
Mrna Levels ◽  
Hsp 70 ◽  
Northern Blots ◽  
Stressed Cells ◽  
Shock Proteins

Neurospora crassa mycelium was heat shocked for intervals varying from 15–180 min. Heat shock mRNA was monitored by hybridization of Northern blots with the Drosophila hsp-70 gene probe and an inducible member of the yeast hsp-70 gene family, YG100. A 2.7 kilobase (kb) transcript, with homology to these two probes, was detected in cultures shocked for 15 min; its levels increased up to 60–90 min and declined thereafter. Sodium arsenite, too, induced the synthesis of this transcript. An additional, constitutively synthesized 2.4-kb transcript was revealed by hybridization with the yeast probe. The synthesis of this message was terminated during heat shock. Hybridization of Northern blots with the Drosophila actin gene probe demonstrated two size classes, 1.85 and 1.63 kb; the former decreased dramatically following heat shock. Recovery, as assessed by the disappearance of the 2.7-kb hsp-70-mRNA and restoration of the 1.85-kb actin message to the prestress levels, was essentially complete within 60 min of transfer to 28 °C. In vitro translations of RNA from stressed cells showed the heat shock messages to be stable and readily translatable. RNA of cells subjected to heat shock plus CdCl2 showed a higher content of messages for heat shock proteins of 70, 80, and 90 kilodaltons.

scholarly journals Nuclear stress granules

2004 ◽  
Vol 164 (1) ◽  
pp. 15-17 ◽  
Author(s):  
Anton Sandqvist ◽  
Lea Sistonen
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Heterochromatic Region ◽  
Stress Granules ◽  
Mrna Processing ◽  
Stress Granule ◽  
Target Sites ◽  
Processing Factors

Nuclear stress granules are subnuclear compartments that form in response to heat shock and other stress stimuli. Although many components of nuclear stress granules have been identified, including HSF1 and pre-mRNA processing factors, their function remains a mystery. A paper in this issue describes the stress-induced transcriptional activation of one of the nuclear stress granule target sites, a heterochromatic region that has been considered silent (Jolly et al., 2004). These intriguing findings will certainly give the research of these structures a new twist.

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