共查询到20条相似文献,搜索用时 484 毫秒
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Heat stress-induced H2O2 is required for effective expression of heat shock genes in Arabidopsis 总被引:5,自引:0,他引:5
The mechanisms of sensing and signalling of heat and oxidative stresses are not well understood. The central question of this
paper is whether in plant cells oxidative stress, in particular H2O2, is required for heat stress- and heat shock factor (HSF)-dependent expression of genes. Heat stress increases intracellular
accumulation of H2O2 in Arabidopsis cell culture. The accumulation was greatly diminished using ascorbate as a scavenger or respectively diphenyleneiodonium
chloride (DPI) as an inhibitor of reactive oxygen species production. The mRNA of heat shock protein (HSP) genes, exemplified
by Hsp17.6, Hsp18.2, and the two cytosolic ascorbate peroxidase genes Apx1, Apx2, reached similar levels by moderate heat stress (37°C) or by treatment with H2O2, butylperoxide and diamide at room temperature. The heat-induced expression levels were significantly reduced in the presence
of ascorbate or DPI indicating that H2O2 is an essential component in the heat stress signalling pathway. Rapid (15 min) formation of heat shock promoter element
(HSE) protein-binding complex of high molecular weight in extracts of heat-stressed or H2O2-treated cells and the inability to form this complex after ascorbate treatment suggests that oxidative stress affects gene
expression via HSF activation and conversely, that H2O2 is involved in HSF activation during the early phase of heat stress. The heat stress induction of a high mobility HSE-binding
complex, characteristic for later phase of heat shock response, was blocked by ascorbate and DPI. H2O2 was unable to induce this complex suggesting that H2O2 is involved only in the early stages of HSF activation. Significant induction of the genes tested after diamid treatment
and moderate expression of the sHSP genes in the presence of 50 mM ascorbate at 37°C occurred without activation of HSF, indicating
that other mechanisms may be involved in stress signalling.
Electronic Supplementary Material Supplementary material is available for this article at http//dx.doi.org/10.1007/s11103-006-0045-4
Roman A. Volkov and Irina I. Panchuk contributed equally 相似文献
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In this study we analyzed how a dosage decrease in mono- and diheterozygotes on both lethal alleles of the lgl-gene and hsf heat shock regulator influences viability and life span at optimal and high temperature 29°C conditions. We found that hsf
1/+ (1 dosage of active hsf -factor) heterozygote animals had significantly increased viability (up to 30–39%) in case of its development from egg to
imago under the stress of 29°C. However, this stress-protective effect of a decreased dosage of HSF1 was suppressed in diheterozygotes,
while the dosage of tumor suppressor lgl was simultaneously decreased. Under stress temperature conditions, a decrease in dosage of one of the alleles also increased
the average life span and delayed aging, especially in the case of maternal inheritance of each of the loss-of-function mutations.
In diheterozygotes the average life span had intermediate meanings. However, in diheterozygote males under stress conditions
the positive longevity effect of hsf was suppressed in the presence of the lgl-mutation. Paradoxically, that decrease of expression of each of the studied vital genes provided a positive effect on both
viability and life span under stress conditions. However, a simultaneous dosage decrease of two loss-of-function alleles in
diheterozygotes resulted in disbalanced effects on the organism level. The received data indicate interaction between HSF1
and LGL gene products during ontogenesis and stress-defending processes. 相似文献
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Activation of Heat shock factor 4-mediated heat shock response is closely associated with postnatal lens development. HSF4 controls the expression of small heat shock proteins (e.g. HSP25 and CRYAB) in lens epithelial cells. However, their roles in modulating lens epithelium homeostasis remain unclear. In this paper, we find that HSF4 is developmentally expressed in mouse lens epithelium and fiber tissue. HSF4 and alpha B-crystallin can selectively protect lens epithelial cells from cisplatin and H2O2 induced apoptosis by stabilizing mitochondrial membrane potential (ΔYm) and reducing ROS production. In addition, to our surprise, HSF4 is involved in upregulating lysosome activity. We found mLEC/HA-Hsf4 cells to have increased DLAD expression, lysosome acidity, cathepsin B activity, and degradation of plasmid DNA and GFP-LC3 protein when compared to mLEC/Hsf4-/- cells. Knocking down Cryab from mLEC/HA-Hsf4 cells inhibits HSF4-mediated lysosome acidification, while overexpression of CRYAB can upregulate cathepsin B activity in mLEC/Hsf4-/- cells. CRAYAB can interact with ATP6V1/A the A subunit of the H+ pump vacuolar ATPase, and is colocalized to lamp1 and lamp2 in the lysosome. Collectively, these results suggest that in addition to modulating anti-apoptosis, HSF4 is able to regulate lysosome activity by at least controlling alpha B-crystallin expression, shedding light on a novel molecular mechanism of HSF4 in regulating lens epithelial cell homeostasis. 相似文献
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《Journal of Asia》2019,22(3):841-846
Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) is one of the most predominant calliphorid species which arrives and colonizes a cadaver first in its native range of the Australian and Oriental regions, and the intra-puparial stage of this species accounts for about half of its immature stage. Therefore, establishing a reliable aging method of the intra-puparial stage of C. megacephala is very important to accurately estimate the minimum postmortem interval (PMImin). In this study, actin was used as an internal reference gene to study the expression of three genes, ecdysone receptor gene ecr, white-eye gene white, and heat shock protein gene hsp70, at different time points during intra-puparial development of C. megacephala. Quantification through real-time PCR revealed that these genes can be used to age the intra-puparial period of C. megacephala as they exhibit regular changes and gene expression level was temperature-dependent. The overall gene expression profile of ecr showed a downward trend throughout the intra-puparial stage. White expression increased steadily until it peaked when intra-puparial development reached 45%, and the expression began to decrease when the intra-puparial development reached 55%. hsp70 was first down-regulated at 0–15% of intra-puparial development, and then slightly up-regulated at 15–40%, and finally down-regulated again until the end of intra-puparial development. This study provides molecular indicators of age during the intra-puparial stage of C. megacephala, and combining gene expression with the morphological methods can lead to more accurate estimation for PMImin. 相似文献