scholarly journals Comparison of the multiple deoxyribonucleic acid-dependent ribonucleic acid polymerase forms of whole rat liver and a minimal-deviation rat hepatoma cell line

1972 ◽  
Vol 126 (3) ◽  
pp. 675-681 ◽  
Author(s):  
C. J. Chesterton ◽  
S M Humphrey ◽  
P H W Butterworth
Keyword(s):  
Cell Line ◽  
Rat Liver ◽  
Animal Cell ◽  
Hepatoma Cell ◽  
Rna Polymerases ◽  
Hepatoma Cell Line ◽  
Enzyme Preparations ◽  
Minimal Deviation ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma

To investigate the possibility that the pattern of multiple DNA-dependent RNA polymerases of an animal cell exerts a controlling influence on its nature, the activities of these enzymes were compared in differentiated rat liver and in a rapidly growing minimal-deviation rat hepatoma cell line by using established techniques of enzyme extraction, separation and determination. Relative to the DNA content of the tissues, RNA polymerase activities of forms AI, AII and B were approx. ninefold, twofold and twofold higher respectively in the cell line than in the liver. Tests indicated that these results could not be explained by differences in extraction efficiency or by the presence of unbound inhibitors or stimulators of polymerase activity in the final enzyme preparations. New forms of the enzyme were not detected in either tissue. The significance of these findings with respect to the possible role of multiple RNA polymerases in the control of cellular activities is discussed.

scholarly journals Expression of the liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase mRNA in FAO-1 cells

1993 ◽  
Vol 293 (1) ◽  
pp. 173-179 ◽  
Author(s):  
C Espinet ◽  
A M Vargas ◽  
M R el-Maghrabi ◽  
A J Lange ◽  
S J Pilkis
Keyword(s):  
Skeletal Muscle ◽  
Cell Line ◽  
Rat Liver ◽  
Hormonal Regulation ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Bifunctional Enzyme ◽  
Dependent Manner ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma

The hormonal regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene expression was studied in the rat hepatoma cell line FAO-1. Both 6-phosphofructo-2-kinase and fructose-2,6-bisphosphatase activities were detected in FAO-1 cells, at 68% of the levels found in rat liver. Northern blot analysis showed that FAO-1 cells, like rat liver, contained a predominant species of bifunctional enzyme mRNA, which is 2.2 kb in size. A sensitive RNAase protection assay revealed the presence in FAO-1 cells of an additional mRNA species, which is generated when transcription is initiated from the skeletal muscle promoter of the rat liver/skeletal muscle gene. The liver/skeletal muscle mRNA ratio in FAO-1 cells was 10:1, which is similar to that observed in rat liver. In contrast, in another rat hepatoma cell line, FTO-2B, only the skeletal muscle mRNA was detected. Insulin and dexamethasone induced the liver bifunctional enzyme mRNA in FAO-1 cells by 2-4-fold and 10-20-fold respectively in a concentration- and time-dependent manner, and their effects were antagonized by cyclic AMP. Transcription of the gene in FAO-1 cells, measured by nuclear run-on assays, was also enhanced by dexamethasone and insulin. It is concluded that the FAO-1 cell line is similar to liver with respect to both the preferential use of the liver promoter of the gene and its regulation by hormones, and is therefore an excellent model for the study of the hepatic expression of this gene.

scholarly journals Identification of a plasma membrane glutamine transporter from the rat hepatoma cell line H4-IIE-C3

2002 ◽  
Vol 368 (1) ◽  
pp. 371-375 ◽  
Author(s):  
Matthew POLLARD ◽  
David MEREDITH ◽  
John D. McGIVAN
Keyword(s):  
Amino Acid ◽  
Cell Line ◽  
Rat Liver ◽  
Hepatoma Cell ◽  
Single Amino Acid ◽  
Hepatoma Cell Line ◽  
Normal Rat ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma ◽  
Glutamine Uptake

Glutamine is taken up into the rat hepatoma cell line H4-IIE-C3 by a Na+-dependent transport system which is specific for glutamine, alanine, serine, cysteine and asparagine and does not tolerate substitution of Na+ by Li+. Glutamine transport was relatively weakly inhibited by a 50-fold excess of leucine and was not inhibited by phenylalanine or N-methyl aminoisobutyrate. These general properties are characteristic of the recently identified ASCT/B0 family of transporters. Using a reverse transcriptase PCR-based homology cloning approach, we have characterized a cDNA for a novel member of this transporter family (H4-ASCT2) from H4-IIE-C3 cells. The cDNA encodes a 551-amino acid protein which exhibits similarities of between 75 and 85% with ASCT/B0 transporters previously cloned from other sources. When expressed in Xenopus oocytes, this transporter catalyses Na+-dependent glutamine uptake with characteristics very similar to those of glutamine uptake into the H4-IIE-C3 cells. This newly characterized transporter possesses a number of amino acid sequence differences from ASCT2 clones recently isolated from rat astroglial cells and from normal rat liver. In particular, the loop region between transmembrane helices 3 and 4 from H4-ASCT2 shares less than 60% sequence similarity with ASCT2 from rat liver; furthermore, there are some 25 single amino acid substitutions elsewhere in the H4-ASCT2 sequence compared with that from rat liver. Thus enhanced glutamine uptake in rat hepatoma cells is mediated by the expression of a novel ASCT/B0 transporter isoform rather than by increased expression of the ASCT2 mRNA found in normal rat liver.

Mechanisms of NADPH – cytochrome P450 oxidoreductase induction by dexamethasone in the H4IIE rat hepatoma cell line

2020 ◽  
Vol 98 (5) ◽  
pp. 267-274
Author(s):  
David S. Riddick ◽  
Anne K. Mullen Grey
Keyword(s):  
Cytochrome P450 ◽  
Cell Line ◽  
Rat Liver ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
P450 Oxidoreductase ◽  
Nadph Cytochrome ◽  
Cytochrome P450 Oxidoreductase ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma

Expression of NADPH – cytochrome P450 oxidoreductase (POR), electron donor for microsomal P450s, is induced in rat liver by dexamethasone (DEX), an activator of the glucocorticoid receptor (GR) and the pregnane X receptor (PXR). DEX induction of POR in rat liver is primarily PXR-mediated, although GR may contribute to mRNA effects. We examined the role of GR and PXR in the DEX induction of POR mRNA and protein in the H4IIE rat hepatoma cell line. The DEX EC50 for a PXR target, CYP3A23, exceeded that for the GR targets tyrosine aminotransferase and PXR as well as POR itself. POR protein levels were induced 3- and 4-fold, respectively, by DEX concentrations activating GR selectively (100 nM) or both GR and PXR (10 μM). POR was induced by triamcinolone acetonide, a selective GR agonist, but not pregnenolone-16α-carbonitrile, a selective PXR agonist. POR induction was blocked by the GR antagonist RU486 but minimally influenced by the PXR antagonist FLB-12. The half-life for POR mRNA was prolonged by DEX at both 100 nM and 10 μM. GR is more important in DEX-induced POR expression in H4IIE cells compared to rat liver in vivo, calling into question the suitability of this cell model for mechanistic studies.

Specific modulation by ethanol of the protein synthesis pattern in the C2 rat hepatoma cell line

1988 ◽  
Vol 6 (1) ◽  
pp. 85-93 ◽  
Author(s):  
M.N. Chobert ◽  
P. Vincens ◽  
G. Guellaën ◽  
R. Barouki ◽  
Y. Laperche ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma

scholarly journals Identification of a somatomedin-binding protein produced by a rat hepatoma cell line

FEBS Letters ◽  
1981 ◽  
Vol 127 (2) ◽  
pp. 225-227 ◽  
Author(s):  
Dan H. Morris ◽  
Don S. Schalch ◽  
Barbara Monty-Miles
Keyword(s):  
Cell Line ◽  
Binding Protein ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Rat Hepatoma Cell Line ◽  
Rat Hepatoma
Sign in / Sign up

Export Citation Format

Share Document