scholarly journals Temperature-sensitive mRNA degradation is an early event in hepatocyte de-differentiation

1997 ◽  
Vol 328 (3) ◽  
pp. 937-944 ◽  
Author(s):  
Xiu-Jun WANG ◽  
P. Conrad HODGKINSON ◽  
C. Matthew WRIGHT ◽  
J. Alan PAINE
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Transcriptional Silencing ◽  
Rnase Activity ◽  
Early Event ◽  
Specific Gene ◽  
Temperature Sensitive ◽  
Mrna Levels ◽  
Cultured Hepatocytes ◽  
Albumin Mrna

The isolation and culture of metabolically active hepatocytes by proteolytic digestion of the extracellular matrix of the liver results in the transcriptional silencing of liver-specific genes encoding cytochromes P-450 (CYP) and albumin together with an induction of cellular RNase activity. The levels of albumin mRNA are maintained in cultured hepatocytes at similar levels to that present in the intact liver for at least 24 h, whereas the major constitutively expressed CYP2C11 mRNA is rapidly degraded. Hepatocytes heat-shocked at 40 °C during the isolation procedure (which results in an induction of heat-shock protein mRNA species) blocks the increase in RNase activity and abrogates the loss of CYP2C11 mRNA for at least 4 h. Cycloheximide-dependent inhibition of protein synthesis blocks the temperature-dependent induction of heat-shock proteins without affecting the protection afforded to CYP2C11 mRNA, indicating that CYP2C11 mRNA levels are not directly dependent on heat-shock protein induction and suggesting that the induction of RNase activity might be responsible for the specific loss of CYP2C11 mRNA in hepatocytes isolated at 37 °C. Differential rates of degradation of CYP2C11 transcribed in vitro and of albumin mRNA are observed in the presence of cellular extracts from cultured hepatocytes isolated at 37 °C (which have maximally induced levels of cellular RNase activity) but not in comparable extracts from cultured hepatocytes isolated at 40 °C, supporting the hypothesis that an RNase activity is induced in culture that specifically degrades CYP2C11 mRNA but not albumin mRNA. These results suggest that an early event in hepatocyte de-differentiation involves the induction of RNase activity in addition to transcriptional silencing of liver-specific genes and that the induced RNase activity demonstrates specificity within liver-specific gene products.

Tumor necrosis factor induces the rapid phosphorylation of the mammalian heat shock protein hsp28

1990 ◽  
Vol 10 (3) ◽  
pp. 1276-1280
Author(s):  
A P Arrigo
Keyword(s):  
Heat Shock ◽  
Tumor Necrosis Factor ◽  
Heat Shock Protein ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Tumor Promoter ◽  
Early Event ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

Tumor necrosis factor alpha was found to rapidly phosphorylate the unique mammalian small heat shock protein hsp28 without impairing its cytoplasmic localization and without inducing the synthesis of the heat shock proteins. In contrast to the C-kinase-dependent phosphorylation of hsp28 in response to the tumor promoter phorbol-12-myristate-13-acetate, the heat- and tumor necrosis factor-mediated phosphorylation of this heat shock protein appears to occur independently of C kinase. These observations suggest that a C-kinase-independent phosphorylation of hsp28 may be an early event in the cellular action of tumor necrosis factor alpha.

scholarly journals Endocrine regulation of heat shock protein mRNA levels in long-lived dwarf mice

2009 ◽  
Vol 130 (6) ◽  
pp. 393-400 ◽  
Author(s):  
William R. Swindell ◽  
Michal M. Masternak ◽  
John J. Kopchick ◽  
Cheryl A. Conover ◽  
Andrzej Bartke ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Mrna Levels ◽  
Endocrine Regulation ◽  
Dwarf Mice

Impaired induction of heat shock protein implicated in decreased thermotolerance in a temperature-sensitive multinucleated cell line

1998 ◽  
Vol 437 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Y. Cao ◽  
Takaaki Matsumoto ◽  
Katsuaki Motomura ◽  
Akira Ohtsuru ◽  
Shunichi Yamashita ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Cell Line ◽  
Temperature Sensitive ◽  
Multinucleated Cell

Increasing stocking density causes inhibition of metabolic–antioxidant enzymes and elevates mRNA levels of heat shock protein 70 in rainbow trout

2011 ◽  
Vol 141 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Ercüment Aksakal ◽  
Deniz Ekinci ◽  
Orhan Erdoğan ◽  
Şükrü Beydemir ◽  
Zuhal Alım ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Rainbow Trout ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Stocking Density ◽  
Mrna Levels

Evaluation of Reference Genes and Age Estimation of Forensically Useful Aldrichina grahami (Diptera: Calliphoridae) During Intrapuparial Period

2020 ◽  
Author(s):  
Zhuoying Liu ◽  
Han Han ◽  
Wei Chen ◽  
Shiwen Wang ◽  
Fanming Meng ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Ribosomal Protein ◽  
Developmental Stage ◽  
Mrna Expression ◽  
Ribosomal Rna ◽  
Reference Genes ◽  
28S Rrna ◽  
Mrna Levels ◽  
Gene Markers

Abstract The minimum postmortem interval (PMImin) could be evaluated from the developmental stage of forensically important insects colonize a corpse, such as blow flies (Diptera: Calliphoridae). Unlike larvae, the developmental stage of which is well established according to their morphology, estimating the age of pupae is proven to be challenging. Recently, several studies reported the regulation of special genes during the development of blow fly pupae. However, gene regulation in Aldrichina grahami during the intrapuparial period remains to be studied. Therefore, we set out to investigate the mRNA levels of heat shock protein 23 (Hsp23), heat shock protein 24 (Hsp24), and 1_16 during the metamorphosis of A. grahami pupae. First, we examined seven candidate reference genes (ribosomal protein 49 (RP49), 18S ribosomal RNA (18S rRNA), 28S ribosomal RNA (28S rRNA), beta-tubulin at 56D (β-tubulin), Ribosomal protein L23 (RPL23), glutathione S-transferase (GST1), and Actin. Three widely used algorithms (NormFinder, BestKeeper, and geNorm) were applied to evaluate the mRNA levels of reference gene candidates in puparium at three stable temperatures (15, 22, and 27°C). Next, mRNA expression of Hsp23, Hsp24, and 1_16 during A. grahami metamorphosis was examined. We demonstrated that mRNA expression levels of Hsp23, Hsp24, and 1_16 showed time-specific regulation. In summary, our study identified three gene markers for the intrapuparial period of A. grahami and might provide a potential application in PMImin estimation.

Protein phosphatase 2C, encoded by ptc1+, is important in the heat shock response of Schizosaccharomyces pombe

1994 ◽  
Vol 14 (6) ◽  
pp. 3742-3751
Author(s):  
K Shiozaki ◽  
H Akhavan-Niaki ◽  
C H McGowan ◽  
P Russell
Keyword(s):  
Heat Shock ◽  
Schizosaccharomyces Pombe ◽  
Protein Phosphatase ◽  
Deletion Mutant ◽  
Protein Phosphatases ◽  
Suppressor Gene ◽  
Temperature Sensitive ◽  
Mrna Levels ◽  
Biological Functions ◽  
Protein Phosphatase 2C

Protein phosphatase 2C (PP2C), an Mg(2+)-dependent enzyme that dephosphorylates serine and threonine residues, defines one of the three major families of structurally unrelated eukaryotic protein phosphatases. Members of the two other families of protein phosphatases are known to have important cellular roles, but very little is known about the biological functions of PP2C. In this report we describe a genetic investigation of a PP2C enzyme in the fission yeast Schizosaccharomyces pombe. We discovered ptc1+ (phosphatase two C) as a multicopy suppressor gene of swo1-26, a temperature-sensitive mutation of a gene encoding the heat shock protein hsp90. The ptc1+ gene product is a 40-kDa protein with approximately 24% identity to a rat PP2C protein. Purified Ptc1 has Mg(2+)-dependent casein phosphatase activity, confirming that it is a PP2C enzyme. A ptc1 deletion mutant is viable and has approximately normal levels of PP2C activity, observations consistent with the fact that ptc1+ is a member of a multigene family. Although a ptc1 deletion mutant is viable, it has a greatly reduced ability to survive brief exposure to elevated temperature. Moreover, ptc1+ mRNA levels increase 5- to 10-fold during heat shock. These data, demonstrating that Ptc1 activity is important for survival of heat shock, provide one of the first genetic clues as to the biological functions of PP2C.

Hepatocyte differentiation initiates during endodermal-mesenchymal interactions prior to liver formation

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 217-225 ◽  
Author(s):  
S. Cascio ◽  
K.S. Zaret
Keyword(s):  
General Pattern ◽  
Cell Aggregation ◽  
Cell Types ◽  
Specific Gene ◽  
Mrna Levels ◽  
Cellular Interactions ◽  
Hepatocyte Differentiation ◽  
Endodermal Cells ◽  
Tissue Matrix ◽  
Albumin Mrna

Previous studies with embryonic tissue explants showed that cellular interactions with mesenchyme are required for endodermal cells to differentiate into hepatocytes. However, these studies assayed hepatocyte characteristics that were evident after days of culture, leaving open the question of whether the primary inductive interactions initiated hepatocyte differentiation, or whether subsequent steps, such as may occur during cell aggregation to form the liver, were necessary. Using the technique of in situ hybridization, we find that serum albumin mRNA, a liver-specific gene product, is first detected in hepatic precursor cells of the endoderm as early as 9.5 days of mouse embryo development, a full day prior to cell aggregation and liver formation. The endodermal cells express albumin mRNA upon migration into strands of connective tissue matrix within mesenchyme. Thus, the onset of differentiation of the endoderm is coincident with its interaction with mesenchyme. Early albumin transcripts are initiated at the same site of the albumin promoter as in adult hepatocytes, suggesting that at least a subset of the transcription factors that control albumin transcription in the adult may be involved in executing the early steps of hepatic determination. We also observe a sharp increase in albumin mRNA levels shortly after the definitive formation of the liver, apparently reflecting cell interactions that enhance hepatocyte differentiation. Hepatocyte differentiation is therefore similar in several respects to pancreatic exocrine cell development, and may represent a general pattern for gut-derived tissues. For both cell types, early interactions with mesenchyme are coincident with the initial expression of differentiated gene products at a low level in proliferating endoderm, and the initial pattern of expression is amplified upon organ formation.

Effects of cycloheximide on thermotolerance expression, heat shock protein synthesis, and heat shock protein mRNA accumulation in rat fibroblasts

1986 ◽  
Vol 6 (4) ◽  
pp. 1088-1094
Author(s):  
R B Widelitz ◽  
B E Magun ◽  
E W Gerner
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Mrna Levels ◽  
Hsp 70 ◽  
Mrna Accumulation ◽  
General Protein Synthesis ◽  
Rat Fibroblasts ◽  
General Protein ◽  
Rat Embryonic Fibroblasts

A single hyperthermic exposure can render cells transiently resistant to subsequent high temperature stresses. Treatment of rat embryonic fibroblasts with cycloheximide for 6 h after a 20-min interval at 45 degrees C inhibits protein synthesis, including heat shock protein (hsp) synthesis, and results in an accumulation of hsp 70 mRNA, but has no effect on subsequent survival responses to 45 degrees C hyperthermia. hsp 70 mRNA levels decreased within 1 h after removal of cycloheximide but then appeared to stabilize during the next 2 h (3 h after drug removal and 9 h after heat shock). hsp 70 mRNA accumulation could be further increased by a second heat shock at 45 degrees C for 20 min 6 h after the first hyperthermic exposure in cycloheximide-treated cells. Both normal protein and hsp synthesis appeared increased during the 6-h interval after hyperthermia in cultures which received two exposures to 45 degrees C for 20 min compared with those which received only one treatment. No increased hsp synthesis was observed in cultures treated with cycloheximide, even though hsp 70 mRNA levels appeared elevated. These data indicate that, although heat shock induces the accumulation of hsp 70 mRNA in both normal and thermotolerant cells, neither general protein synthesis nor hsp synthesis is required during the interval between two hyperthermic stresses for Rat-1 cells to express either thermotolerance (survival resistance) or resistance to heat shock-induced inhibition of protein synthesis.

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