Search results for "HEAT-SHOCK PROTEINS"
showing 10 items of 310 documents
Cadmium induces the expression of specific stress proteins in sea urchin embryos.
2004
Abstract Marine organisms are highly sensitive to many environmental stresses, and consequently, the analysis of their bio-molecular responses to different stress agents is very important for the understanding of putative repair mechanisms. Sea urchin embryos represent a simple though significant model system to test how specific stress can simultaneously affect development and protein expression. Here, we used Paracentrotus lividus sea urchin embryos to study the effects of time-dependent continuous exposure to subacute/sublethal cadmium concentrations. We found that, between 15 and 24 h of exposure, the synthesis of a specific set of stress proteins (90, 72–70, 56, 28, and 25 kDa) was ind…
Studies on heat shock proteins in sea urchin development
1999
Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra- embryonic and intracellular hsp location has…
Sea urchin embryos as an in vivo model for the assessment of manganese toxicity: developmental and stress response effects.
2009
In the marine environment increasing concentrations of bio-available compounds often result from anthropogenic activities. Among metal ions, manganese represents a new emergent factor in environmental contamination. Here, we studied the effects of manganese on Paracentrotus lividus sea urchin embryos using biological and biochemical approaches for the analysis of impact on development, tissue accumulation and stress markers. Embryos were continuously exposed from fertilization to manganese at concentrations ranging from 1.0 to 61.6 mg l(-1), monitored for developmental abnormalities at 48 h after fertilization, and used for atomic spectrometric analysis at various times from 6 to 72 h. We f…
Sea urchin HSF activity in vitro and in transgenic embryos.
1997
Evidence is provided for the presence at the physiological temperature of 20 degrees C of a heat shock transcriptor factor, HSF, in the nuclei of P.lividus embryos. This HSF is able to specifically bind in vitro the heat shock element, HSE, of the promoter of the hsp70 gene i.v., as suggested by DNA-protein binding reactions and DNAse I protection assays. Upon heat-shock, at the temperature of 31 degrees C, its ability to bind the HSE units becomes much higher. The HSF activated by heat-shock drives in vivo the transcription of the beta-galactosidase reporter gene in transgenic sea urchin gastrulae. An ATF-like transcription factor, widely described in other organisms but not at all in sea …
Mitochondrial localization and temporal expression of the Drosophila melanogaster DnaJ homologous tumor suppressor Tid50
1998
The Drosophila melanogaster tumor suppressor gene lethal(2)tumorous imaginal discs (tid) was identified as a homolog of all dnaJ-like genes known to date which have been well preserved in evolution. Homozygous D. melanogaster l(2)tid mutants l(2)tid1, l(2)tid2 and l(2)tid3 are characterized by neoplastic transformation of the adult integumental primordia, the imaginal discs, and the death at the time of puparium formation. The first part of this study is concerned with the identification and subcellular localization of the l(2)tid-encoded protein, Tid50. The second part examines its tissue specific expression during wild-type development and in tumorous imaginal discs. To specify the functi…
EGTA treatment causes the synthesis of heat shock proteins in sea urchin embryos.
2000
Paracentrotus lividus embryos, at post-blastular stage, when subjected to a rise in temperature from physiologic (20 degrees C) to 31 degrees C, synthesize a large group of heat shock proteins (hsps), and show a severe inhibition of bulk protein synthesis. We show, by mono- and two-dimensional electrophoresis, that also EGTA (ethylene glycol-bis[beta-aminoethyl ether] tetraacetic acid) treatment induces in sea urchin embryos both marked inhibition of bulk protein synthesis and the synthesis of the entire set of hsps. Furthermore, EGTA-treated sea urchin embryos are able to survive at a temperature otherwise lethal (35 degrees C) becoming thermotolerant. Because incubation with a different c…
High levels of the molecular chaperone Mdg1/ERdj4 reflect the activation state of endothelial cells
2003
Mdg1/ERdj4, a mammalian chaperone that belongs to the HSP40 protein family, has been reported to be located in the endoplasmic reticulum (ER), is induced by ER stress, and protects ER stressed cells from apoptosis. Here we show that under normal physiological conditions, Mdg1/ERdj4 is expressed at various levels in the vasculature due to different activation states of the endothelium. To elucidate the stimuli that induce ER stress and thus upregulate Mdg1/ERdj4, we investigated the effect of several endothelium specific stressors on its expression. Mdg1/ERdj4 mRNA is induced by activated macrophages, by nitric oxide (NO) and heat shock, and during terminal cell differentiation, whereas shea…
A field methodology to study effects of UV radiation on fish larvae.
2003
There is a considerable lack of in situ specific information about the effects of UV-B radiation on limnic animals studied in the field. We exposed larval pike (Esox lucius L.) in two types of cuvettes (glass and quartz) placed at different depths (5 or 15 cm) to natural solar UV or to artificially enhanced UV-B (lamps on 3 h per day), simulating the scenarios for coming decades. Dose realism and comparability with earlier laboratory experiments was the main purpose, and therefore UV-B irradiances to the surface as well as underwater irradiances were directly measured. Result showed that UV-B dose rates in natural waters are low even though DOC concentration was low (4.8 mg/l) in our study …
Small heat shock proteins and the cytoskeleton: an essential interplay for cell integrity?
2012
Abstract The cytoskeleton is a highly complex network of three major intracellular filaments, microfilaments (MFs), microtubules (MTs) and intermediate filaments (IFs). This network plays a key role in the control of cell shape, division, functions and interactions in animal organs and tissues. Dysregulation of the network can contribute to numerous human diseases. Although small HSPs (sHSPs) and in particular HSP27 (HSPB1) or αB-crystallin (HSPB5) display a wide range of cellular properties, they are mostly known for their ability to protect cells under stress conditions. Mutations in some sHSPs have been found to affect their ability to interact with cytoskeleton proteins, leading to IF a…
Extracellular Hsp70 Enhances Mesoangioblast Migration via an Autocrine Signaling Pathway
2016
Mouse mesoangioblasts are vessel-associated progenitor stem cells endowed with the ability of multipotent mesoderm differentiation. Therefore, they represent a promising tool in the regeneration of injured tissues. Several studies have demonstrated that homing of mesoangioblasts into blood and injured tissues are mainly controlled by cytokines/chemokines and other inflammatory factors. However, little is known about the molecular mechanisms regulating their ability to traverse the extracellular matrix (ECM). Here, we demonstrate that membrane vesicles released by mesoangioblasts contain Hsp70, and that the released Hsp70 is able to interact by an autocrine mechanism with Toll-like receptor …