scholarly journals Importance of the 3′ untranslated region of ornithine decarboxylase mRNA in the translational regulation of the enzyme

2001 ◽  
Vol 356 (2) ◽  
pp. 627-634 ◽  
Author(s):  
Eva LÖVKVIST WALLSTRÖM ◽  
Koichi TAKAO ◽  
Anna WENDT ◽  
Cristina VARGIU ◽  
Hong YIN ◽  
...  
Keyword(s):  
Feedback Control ◽  
Ornithine Decarboxylase ◽  
Translational Control ◽  
Translational Regulation ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Specific Effect ◽  
Untranslated Regions ◽  
Ovary Cells ◽  
Stable Transfectants

Translational regulation of ornithine decarboxylase (ODC), which catalyses the first step in the biosynthesis of polyamines, appears to be an important mechanism in the strong feedback control as well as in the hypotonic induction of the enzyme. However, the exact mechanisms are not yet understood. The ODC mRNA has long 5′ and 3′ untranslated regions (UTRs) which may be involved in the translational control of the enzyme. In the present study we have used a series of stable transfectants of Chinese Hamster ovary cells expressing ODC mRNAs with various truncations in the 5′ and 3′ UTRs to investigate the importance of these regions. It is demonstrated that neither the 5′ UTR nor the 3′ UTR appears to be involved in the polyamine-mediated feedback control of ODC synthesis. The hypotonic induction of ODC, on the other hand, was shown to be highly dependent on the presence of the 3′ UTR, but not on the 5′ UTR, of ODC mRNA. Cells expressing ODC mRNAs lacking the 3′ UTR showed no, or only a very slight, induction of ODC whether the 5′ UTR was present or not, whereas the cell lines expressing ODC mRNAs containing the 3′ UTR (with or without the 5′ UTR) markedly induced ODC after a hypotonic shock. The present finding of a role for the ODC mRNA 3′ UTR in the hypotonic induction of ODC is the first demonstration of a specific effect of the 3′ UTR in the regulation of ODC.

Lipopolysaccharide and serum synergistically stimulate ornithine decarboxylase in Chinese hamster ovary cells

In Vitro ◽  
1984 ◽  
Vol 20 (11) ◽  
pp. 876-878 ◽  
Author(s):  
Anne Rissa L. Greenfield ◽  
Steven M. Taffet ◽  
Mari K. Haddox
Keyword(s):  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells

scholarly journals Polyamine starvation causes accumulation of cadaverine and its derivatives in a polyamine-dependent strain of Chinese-hamster ovary cells

1983 ◽  
Vol 210 (3) ◽  
pp. 945-948 ◽  
Author(s):  
E Hölttä ◽  
P Pohjanpelto
Keyword(s):  
Cell Proliferation ◽  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Specific Inhibitor ◽  
Ovary Cells ◽  
Serum Free ◽  
Dependent Strain

Starvation of the polyamine-dependent Chinese-hamster ovary cells for ornithine or ornithine-derived polyamines in serum-free culture resulted in the formation of cadaverine and its aminopropyl derivatives, N-(3-aminopropyl)cadaverine and NN'-bis(3-aminopropyl)cadaverine. The synthesis of these unusual amines was inhibited by treatment of the cells with DL-2-difluoromethylornithine, a specific inhibitor of ornithine decarboxylase (EC 4.1.1.17). In the absence of ornithine (the normal substrate), ornithine decarboxylase thus appeared to catalyse the decarboxylation of lysine to cadaverine. Cell proliferation was markedly inhibited by ornithine deprivation of the cells, and further depressed by exposure of the cultures to difluoromethylornithine.

scholarly journals Conservation of promoter sequence but not complex intron splicing pattern in human and hamster genes for 3-hydroxy-3-methylglutaryl coenzyme A reductase.

1987 ◽  
Vol 7 (5) ◽  
pp. 1881-1893 ◽  
Author(s):  
K L Luskey
Keyword(s):  
Transcription Initiation ◽  
Untranslated Region ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Untranslated Regions ◽  
Hmg Coa Reductase ◽  
Ovary Cells ◽  
Splicing Pattern ◽  
Reductase Gene ◽  
Coa Reductase

Regulation of the expression of 3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase is a critical step in controlling cholesterol synthesis. Previous studies in cultured Chinese hamster ovary cells have shown that HMG-CoA reductase is transcribed from a cholesterol-regulated promoter to yield a heterogeneous collection of mRNAs with 5' untranslated regions of 68 to 670 nucleotides in length. Synthesis of these molecules is initiated at multiple sites, and multiple donor sites are used to excise an intron in the 5' untranslated region. In the current paper, I report that human HMG-CoA reductase gene resembles the Chinese hamster gene in having multiple sites of transcription initiation that are subject to suppression by cholesterol. The human gene differs from the hamster gene in that a single donor splice site is used to excise the intron in the 5' untranslated region. All of the resulting RNAs have short 5' untranslated regions of 68 to 100 nucleotides. This difference in the splicing pattern of the first intron is species specific and not a peculiarity of cultured cells in that HMG-CoA reductase mRNAs from Syrian hamster livers resemble those of the cultured Chinese hamster ovary cells. Comparison of the DNA sequences of the HMG-CoA reductase promoters from three different species--humans, Syrian hamsters, and Chinese hamsters--shows a highly conserved region of 179 nucleotides that extends from 220 to 42 nucleotides upstream of the transcription initiation sites. This region is 88% identical between the human and Chinese hamster promoter. When fused to the coding region of the Escherichia coli chloramphenicol acetyltransferase gene, this highly conserved region of the reductase gene directs the cholesterol-regulated expression of chloramphenicol acetyltransferase in transfected hamster cells, further indicating the interspecies conservation of the regulatory elements.

scholarly journals Polyamine-mediated turnover of ornithine decarboxylase in Chinese-hamster ovary cells

1986 ◽  
Vol 236 (2) ◽  
pp. 351-357 ◽  
Author(s):  
J R Glass ◽  
E W Gerner
Keyword(s):  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Specific Activity ◽  
Binding Protein ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Defined Medium ◽  
Ovary Cells ◽  
Exogenous Substrate ◽  
Polyamine Content

We have used Chinese-hamster ovary (CHO) cells maintained in a chemically defined medium to study the regulation of ornithine decarboxylase (ODC) by polyamines. Cells maintained in the defined medium had no detectable putrescine, and approx. 1-3 units of ODC activity/10(6) cells, where 1 unit corresponds to 1 nmol of substrate decarboxylated in 30 min. The defined medium is ornithine-deficient, thus limiting the exogenous substrate for ODC, and subsequently decreasing intracellular polyamine accumulation. Restoration of intracellular putrescine and increased formation of spermidine by addition of exogenous ornithine or putrescine led to a marked decrease in ODC activity, which was paralleled by a decrease in a alpha-DL-difluoromethyl[3,4-3H]ornithine (DFMO)-binding protein of Mr approx. 53,000, which is precipitable with anti-ODC antibody. Calculation of DFMO binding per unit of activity showed no change in the specific activity of the enzyme. We identified [35S]methionine-labelled peptides corresponding to ODC by immunoprecipitation of radiolabeled whole cell proteins. Only one protein was precipitated, of Mr approx. 53 000, which co-migrated with the DFMO-binding protein. Immunoprecipitation of radiolabelled proteins from cells incubated in the presence of exogenous ornithine indicated that the observed activity decrease was not due to an inhibition of ODC protein synthesis. Analysis of immunoprecipitable ODC protein from cells that had been pulse-labelled with [35S]methionine, and then treated for 5 h with 100 microM-ornithine, -putrescine or -spermidine, revealed a distinct disappearance of labelled ODC protein after restoration of intracellular polyamine pools. No detectable turnover of ODC was observed in the absence of exogenous polyamine treatment. These data support the hypothesis that ODC protein, and subsequent activity, is regulated by intracellular polyamine content through mechanisms that influence turnover of the enzyme.

Amplification and expression of heterologous ornithine decarboxylase in Chinese hamster cells

1988 ◽  
Vol 8 (2) ◽  
pp. 764-769
Author(s):  
T R Chiang ◽  
L McConlogue
Keyword(s):  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Types ◽  
Wild Type ◽  
Dominant Marker ◽  
Ovary Cells ◽  
Mammalian Expression ◽  
Mammalian Expression Vector

We have developed an amplifiable mammalian expression vector based on the enzyme ornithine decarboxylase (ODC). We show greater than 700-fold amplification of this vector in ODC-deficient Chinese hamster ovary cells. A passive coamplified marker, dihydrofolate reductase (dhfr), was amplified and overexpressed 1,000-fold. This ODC vector was a dominant marker in a variety of cell types and displayed at least 300-fold amplification in wild-type Chinese hamster ovary cells.

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