scholarly journals Accumulation of ornithine decarboxylase-antizyme complex in HMOA cells

1985 ◽  
Vol 225 (3) ◽  
pp. 689-697 ◽  
Author(s):  
Y Murakami ◽  
K Fujita ◽  
T Kameji ◽  
S Hayashi
Keyword(s):  
Tissue Culture ◽  
Complex Formation ◽  
Ornithine Decarboxylase ◽  
New Method ◽  
Htc Cells ◽  
Hepatoma Tissue

A new method was developed for the assay of ornithine decarboxylase (ODC)-antizyme complex, in which alpha-difluoromethylornithine (DFMO)-inactivated ODC was used to release active ODC competitively from the complex. ODC-antizyme complex was present in the extracts of hepatoma tissue-culture (HTC) cells and of ODC-stabilized variant HMOA cells, in much larger amounts in the latter. Cellular amounts of the complex fluctuated after a change of medium in a similar manner in HTC and HMOA cells, increasing during the period of ODC decay. After treatment with cycloheximide, the decay of ODC-antizyme complex in HMOA cells was more rapid than the decay of free ODC, but it was much slower than the decay of free ODC or complexed ODC in HTC cells. Administration of putrescine caused a rapid increase in the amount of ODC-antizyme complex in both HTC and HMOA cells, but nevertheless the decay of total ODC (free ODC plus ODC-antizyme complex) was more rapid with putrescine than with cycloheximide. These results suggested the possibility that ODC is degraded through complex-formation with antizyme. In contrast with complexed antizyme, free antizyme was not stabilized in HMOA cells.

scholarly journals Cloning and expression of two ornithine decarboxylase forms from HMOA cells

1995 ◽  
Vol 312 (1) ◽  
pp. 13-16
Author(s):  
R Autelli ◽  
L Persson ◽  
F M Baccino
Keyword(s):  
Tissue Culture ◽  
Ornithine Decarboxylase ◽  
Half Life ◽  
Turnover Rate ◽  
Cloning And Expression ◽  
Single Amino Acid ◽  
Turnover Rates ◽  
Wild Type ◽  
First Time ◽  
Hepatoma Tissue

In HMOA cells [Mamont, Duchesne, Grove and Tardif (1978) Exp. Cell Res. 115, 387-393] the half-life of ornithine decarboxylase (ODC) is 8-14 h instead of 15 min as in the Hepatoma Tissue Culture parental cells, due to a single amino acid substitution [Miyazaki, Matsufuji, Murakami and Hayashi (1993) Eur. J. Biochem. 214, 837-844]. We demonstrate for the first time that HMOA cells possess two forms of ODC mRNA that are translated into two proteins differing greatly in turnover rates. We have cloned and transfected the cDNAs for the two ODC forms into COS-1 cells for a direct measurement of their turnover rate. The variant ODC form was much more stable than the wild-type protein, with a half-life of 14 h as compared with 2.5 h.

scholarly journals Involvement of the proteasome and antizyme in ornithine decarboxylase degradation by a reticulocyte lysate

1993 ◽  
Vol 295 (1) ◽  
pp. 305-308 ◽  
Author(s):  
Y Murakami ◽  
S Matsufuji ◽  
K Tanaka ◽  
A Ichihara ◽  
S Hayashi
Keyword(s):  
Tissue Culture ◽  
Ornithine Decarboxylase ◽  
Cho Cells ◽  
Chinese Hamster ◽  
Complete Loss ◽  
Protein Inhibitor ◽  
Whole Cells ◽  
Main Pathway ◽  
Reticulocyte Lysate ◽  
Hepatoma Tissue

Ornithine decarboxylase (ODC) degradation in a freshly prepared reticulocyte lysate was examined. Immunodepletion of proteasomes from the reticulocyte lysate resulted in almost complete loss of ODC degradation. In contrast with the previously reported degradation in extracts of hepatoma tissue-culture (HTC) and Chinese-hamster ovary (CHO) cells or that by the purified 26 S proteasome, efficient degradation of ODC was observed in the lysate without exogenous antizyme, an ODC protein inhibitor induced by polyamines, owing to the presence of a significant amount of antizyme in the lysate. The degradation of ODC in the lysate was strongly suppressed on inactivation of antizyme in the lysate with antizyme inhibitor, a protein which binds to the antizyme and releases ODC from the ODC-antizyme complex. Thus the main pathway for ODC degradation in a reticulocyte lysate was essentially the same as that characterized previously in extracts of HTC and CHO cells, namely an ATP- and antizyme-dependent 26 S proteasome-catalysed pathway that is presumed to be responsible for ODC degradation in whole cells.

scholarly journals Tyrosine aminotransferase sensitivity to bromodeoxyuridine during restricted intervals of S phase in hepatoma cells.

1980 ◽  
Vol 87 (3) ◽  
pp. 629-632 ◽  
Author(s):  
J C O'Brien
Keyword(s):  
Tissue Culture ◽  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Rna Synthesis ◽  
Tyrosine Aminotransferase ◽  
S Phase ◽  
Protein And Rna Synthesis ◽  
Htc Cells ◽  
Hepatoma Tissue ◽  
Dna Incorporation

Synchronized hepatoma tissue culture (HTC) cells, accumulated at the G1/S boundary with aminopterin, were released into S phase with either thymidine or 5-bromodeoxyuridine (BUdR). Tyrosine aminotransferase (TAT) activity was found to be unaffected by BUdR over the initial 3 h of S phase, but then to rapidly decline to a new basal level of 40% of control by 9 h. There was no corresponding response in the activities of alcohol dehydrogenase, malate dehydrogenase, acid phosphatase, and alkaline phosphatase, or in the rate of protein and RNA synthesis. If BUdR incorporation was restricted to limited periods of S phase, TAT was found to be maximally suppressed by incorporation into the initial 40% of the DNA. Incorporation of the analogue into the latter 60% of DNA synthesized during S phase had no effect on TAT. This is the first report that the effect of BUdR on TAT in HTC cells is associated with incorporation of the analog into DNA synthesized during a specific interval of S phase.

Hepatoma tissue culture (HTC) cells as a model for investigating the effects of low concentrations of herbicide on cell structure and function

2008 ◽  
Vol 22 (8) ◽  
pp. 1853-1860 ◽  
Author(s):  
M. Malatesta ◽  
F. Perdoni ◽  
G. Santin ◽  
S. Battistelli ◽  
S. Muller ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Cell Structure ◽  
Structure And Function ◽  
Low Concentrations ◽  
Htc Cells ◽  
And Function ◽  
Hepatoma Tissue

scholarly journals INVESTIGATION OF HYPOLIPIDEMIC EFFECT OF SESQUITERPENE Γ-LACTONE AHILLIN IN HEPATOMA TISSUE CULTURE (HTC) CELLS

2014 ◽  
Vol 13 (5) ◽  
pp. 28-35
Author(s):  
V. V. Ivanov ◽  
A. V. Ratkin ◽  
Yu. A. Pfarger ◽  
O. A. Kaidash ◽  
N. V. Ryazantseva ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Hypolipidemic Effect ◽  
Htc Cells ◽  
Hepatoma Tissue

scholarly journals Decreased protein-synthetic activity is an early consequence of spermidine depletion in rat hepatoma tissue-culture cells

1984 ◽  
Vol 217 (3) ◽  
pp. 731-741 ◽  
Author(s):  
B B Rudkin ◽  
P S Mamont ◽  
N Seiler
Keyword(s):  
Tissue Culture ◽  
Culture Medium ◽  
Synthetic Activity ◽  
Cell Culture Medium ◽  
Irreversible Inhibitor ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Htc Cells ◽  
Rat Hepatoma ◽  
Hepatoma Tissue

Hepatoma tissue-culture (HTC) cells were exposed to DL-alpha-difluoromethylornithine (DFMeOrn), a specific irreversible inhibitor of ornithine decarboxylase. Concomitantly with the decrease in spermidine, a decrease in the amount of ribosomes in polyribosomes was observed. Spermine concentrations remained essentially comparable with those in cells not exposed to this inhibitor. Exposure of putrescine- and spermidine-depleted HTC cells to spermidine or spermine rapidly reversed the effect of DFMeOrn on polyribosome profiles, whereas addition of putrescine to the cell culture medium had an effect only after its transformation into spermidine and spermine. The results show that the perturbation of polyribosome formation in DFMeOrn-treated HTC cells is due to spermidine deficiency and that a normal polyamine complement is required for optimal protein-synthetic activity in these cells. The results also indicate that protein synthesis is perturbed before DNA synthesis during depletion of putrescine and spermidine in HTC cells.

scholarly journals Dexamethasone regulates the program of secretory glycoprotein synthesis in hepatoma tissue culture cells

1980 ◽  
Vol 85 (1) ◽  
pp. 1-8 ◽  
Author(s):  
H Baumann ◽  
TD Gelehrter ◽  
D Doyle
Keyword(s):  
Tissue Culture ◽  
Plasma Membrane ◽  
Polyacrylamide Gel Electrophoresis ◽  
Primary Cultures ◽  
Secretory Proteins ◽  
Membrane Glycoprotein ◽  
Glycoprotein Synthesis ◽  
Secretory Glycoproteins ◽  
Htc Cells ◽  
Hepatoma Tissue

The secretory glycoproteins synthesized by hepatoma tissue culture (HTC) cells were resolved by two-dimensional polyacrylamide gel electrophoresis of media from cells that were grown in the presence of [(3)H]fucose. These cells synthesize and secrete a complex set of fucose-containing glycoproteins. These secretory glycoproteins are distinct from those glycoproteins present in the plasma membrane of HTC cells. Incubation of HTC cells with dexamethasone has a pronounced effect on the quality and quantity (denoted here as the program) of secretory protein synthesis, as assayed by the short-term incorporation of labeled mannose, fucose, or methionine. The synthesis of two mannose- and fucose- containing glycoprotein series, one of 50,000 mol wt and a more heterogeneous series with mol wt of 35,000-50,000, is increased to a high level by the hormone; conversely, the synthesis of other secretory proteins, particularly one with mol wt of 70,000, is decreased or stopped completely. The synthesis of some major secretory proteins is not affected by the hormone. Dexamethasone has less of an effect on the composition of either total cell membrane glycoprotein or plasma membrane glycoprotein. But there is a decrease in the synthesis of a major membrane glycoprotein series with mol wt of 140,000. These effects of dexamethasone are relatively specific to HTC cells. Neither Reuber H-35 cells nor primary cultures of rat hepatocytes show the same response to the steroid. Two variant HTC cell lines, which were selected for their resistance to dexamethasone inhibition of extracellular plasminogen activator activity, respond only partially to the steroid-induced regulation of the secretory and membrane glycoproteins.

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