scholarly journals Increase in S-adenosylmethionine decarboxylase in SV-3T3 cells treated with S-methyl-5′-methylthioadenosine

1987 ◽  
Vol 244 (1) ◽  
pp. 49-54 ◽  
Author(s):  
A E Pegg ◽  
R Wechter ◽  
A Pajunen
Keyword(s):  
Translation Efficiency ◽  
3T3 Cells ◽  
Enzyme Protein ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Additional Stabilization ◽  
Key Enzyme ◽  
Translatable Mrna ◽  
Synthase Inhibitor

Treatment of SV-3T3 cells with the spermine synthase inhibitor S-methyl-5′-methylthioadenosine [AdoS+(CH3)2] led to a large increase in the activity of S-adenosylmethionine decarboxylase (AdoMetDC) without affecting ornithine decarboxylase. The elevation of AdoMetDC activity was due to an increased amount of enzyme protein, as demonstrated by radioimmunoassay and by immunoblotting. The increase in AdoMetDC protein was caused by at least three factors: an increase in the amount of translatable mRNA, an increased translation efficiency of the mRNA and an increase in the half-life of the protein. The depletion of spermine brought about by AdoS+(CH3)2 appeared to be responsible for the increased synthesis of AdoMetDC and for part of the decrease in its rate of degradation. An additional stabilization of the enzyme protein was probably due to the binding of AdoS+(CH3)2, which is also a weak inhibitor of AdoMetDC. These results demonstrate the importance of cellular spermine concentrations in regulating the activity of AdoMetDC, which is a key enzyme controlling polyamine synthesis.

scholarly journals Role of the 5′-untranslated region of mRNA in the synthesis of S-adenosylmethionine decarboxylase and its regulation by spermine

1994 ◽  
Vol 302 (3) ◽  
pp. 765-772 ◽  
Author(s):  
L M Shantz ◽  
R Viswanath ◽  
A E Pegg
Keyword(s):  
Secondary Structure ◽  
Untranslated Region ◽  
Fold Increase ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Coding Region ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Synthase Inhibitor

S-Adenosylmethionine decarboxylase (AdoMetDC), a rate-limiting enzyme in polyamine biosynthesis, is regulated by polyamines at the levels of both transcription and translation. Two unusual features of AdoMetDC mRNA are a long (320 nt) 5′-untranslated region (5′UTR), which is thought to contain extensive secondary structure, and a short (15 nt) open reading frame (ORF) within the 5′UTR. We have studied the effects of altering these elements on both the expression of AdoMetDC and its regulation by n-butyl-1,3-diaminopropane (BDAP), a spermine synthase inhibitor. Human AdoMetDC cDNAs containing alterations in the 5′UTR, as well as chimaeric constructs in which the AdoMetDC 5′UTR was inserted ahead of the luciferase-coding region, were transfected into COS-7 cells. Construct pSAM320, which contains all of the 5′UTR, the AdoMetDC protein-coding region and the 3′UTR, was expressed poorly (2-fold over the endogenous activity). Deletion of virtually the entire 5′UTR, leaving nt -12 to -1, increased expression 59-fold, suggesting that 5′UTR acts as a negative regulator. The same effect was seen when the 27 nt at the extreme 5′ end were removed (pSAM293, 47-fold increase), or when the internal ORF which is present in this region was destroyed by changing the ATG to CGA (pSAM320-ATG, 38-fold increase). The expression and regulation of pSAM44 (made by deleting nt -288 to -12), which has very little predicted secondary strucutre, was very similar to that of pSAM320 indicating that the terminal 27 nt including the internal ORF rather than extensive secondary structure may be responsible for the low basal levels of AdoMetDC expression. These results, confirmed using luciferase constructs, suggest that the negative effect on expression is predominantly due to the internal ORF. Depletion of spermine by BDAP increased the expression from pSAM320 more than 5-fold without affecting AdoMetDC mRNA levels. Expression from pSAM293 was unchanged by spermine depletion, whereas that from pSAM320-ATG was increased 2.5-fold. These results indicate the presence of a spermine response element in the first 27 nt of the 5′UTR that may include but is not entirely due to the internal ORF.

scholarly journals Effects of bis(guanylhydrazones) on the activity and expression of ornithine decarboxylase

1985 ◽  
Vol 231 (1) ◽  
pp. 213-216 ◽  
Author(s):  
P Nikula ◽  
L Alhonen-Hongisto ◽  
J Jänne
Keyword(s):  
Ornithine Decarboxylase ◽  
Parent Compound ◽  
Transcriptional Level ◽  
Enzyme Protein ◽  
Adenosylmethionine Decarboxylase ◽  
Intracellular Degradation ◽  
Key Enzyme ◽  
Derivatives Of ◽  
Massive Accumulation ◽  
Stimulation Of

Derivatives of glyoxal bis(guanylhydrazone) (GBG), such as methylglyoxal bis(guanylhydrazone) and ethylglyoxal bis(guanylhydrazone), are potent inhibitors of S-adenosylmethionine decarboxylase (EC 4.1.1.50), the key enzyme required for the synthesis of spermidine and spermine. These compounds, but not the parent compound, induce a massive accumulation of putrescine, partly by blocking the conversion of putrescine into spermidine, but also by strikingly stimulating ornithine decarboxylase (ODC; EC 4.1.1.17) activity. The mechanism of the stimulation of ODC activity and enhanced accumulation of the enzyme protein apparently involved a distinct stabilization of the enzyme against intracellular degradation. However, although the parent compound GBG also stabilized ODC, it powerfully inhibited the enzyme activity and the accumulation of immunoreactive protein in cultured L1210 leukaemia cells. Kinetic considerations indicated that, in addition to the stabilization, all three compounds, GBG in particular, inhibited the expression of ODC. It is unlikely that the decreased rate of synthesis of ODC was attributable to almost unaltered amounts of mRNA in drug-treated cells, thus supporting the view that especially GBG apparently depressed the expression of ODC at some post-transcriptional level.

scholarly journals Studies of non-metabolizable polyamines that support growth of SV-3T3 cells depleted of natural polyamines by exposure to α-difluoromethylornithine

1988 ◽  
Vol 254 (2) ◽  
pp. 373-378 ◽  
Author(s):  
S Nagarajan ◽  
B Ganem ◽  
A E Pegg
Keyword(s):  
Cell Growth ◽  
Physiological Role ◽  
3T3 Cells ◽  
Polyamine Synthesis ◽  
Spermine Synthase ◽  
Support Cell ◽  
Polyamine Derivatives ◽  
Metabolic Interconversion

A number of synthetic polyamine derivatives that included five achiral gem-dimethylspermidines and two analogous tetramethylated spermines were tested for their abilities to serve as substrates for enzymes metabolizing polyamines and for their capacities to substitute for the natural polyamines in cell growth. It was found that none of the compounds were effective substrates for spermine synthase, and only one, namely 8,8-dimethylspermidine, was a substrate for spermidine/spermine N1-acetyltransferase. However, all of the spermidine derivatives and 1,1,12,12-tetramethylspermine were able to support the growth of SV-3T3 cells in which endogenous polyamine synthesis was prevented by the addition of alpha-difluoromethylornithine. These results suggest that either spermidine or spermine can support cell growth without the need for metabolic interconversion. In contrast with the result with 1,1,12,12-tetramethylspermine, 3,3,10,10-tetramethylspermine did not restore growth of polyamine-depleted SV-3T3 cells. Comparison of the properties of these derivatives may prove valuable in understanding the physiological role of polyamines.

scholarly journals Functional Characterization of S-adenosylmethionine Decarboxylase and Spermine Synthase Genes from Apple

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 756A-756
Author(s):  
Hiroyasu Kitashiba* ◽  
Yu-Jin Hao ◽  
Chikako Honda ◽  
Masayuki Kita ◽  
Takaya Moriguchi
Keyword(s):  
Stress Responses ◽  
Functional Characterization ◽  
Growth Speed ◽  
Enzymatic Reactions ◽  
Translation Efficiency ◽  
Lower Growth ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Physiological Processes ◽  
Small Orfs

Polyamines [putrescine (put), spermidine (spd), and spermine (spm)] are aliphatic amines that are implicated in the regulation of many basic physiological processes such as cell growth, proliferation and stress responses in organisms including plants (Walden et al. 1997). Put is metabolized to spd and spm through the successive enzymatic reactions of spd synthase (SPDS) and spm synthase (SPMS) with the use of decarboxylated S-adenosylmethionine (dcSAM) as an aminopropyl donor, which is generated by SAM decarboxylase (SAMDC). So far, two MdSAMDC (MdSAMDC1 and MdSAMDC2) homologous to SAMDC and two MdACL5 (MdACL5-1 and MdACL5-2) homologous to ACL5 encoding SPMS in Arabidopsis (Hanzawa et al. 2000) were isolated from `Orin' apple. To investigate the function of these genes, complementation analyses were carried out using yeast mutants. Each of the MdSAMDCs consists of three ORFs; tiny- and small-ORFs in the 5' regions, and main ORF like other plant SAMDC genes. Both constructs for MdSAMDC containing all ORFs (SAM-DCall) or containing only main ORF (SAMDCorf) were capable of recovering the growth of yeast SAMDC-deficient mutants (delta spe2) without supplement of spd, although the SAMDCall constructs always showed the lower growth speed than the SAMDCorf constructs. On the other hand, yeast SPMS-deficient mutant (delta spe4) introduced by MdACL5 cDNA produced significantly higher amount of spm than the delta spe4 with control vector by HPLC. Collectively, these results suggest that both MdSAMDCs are functional as a SAMDC and the tiny- and small-ORFs are negative-regulatory factor for the translation efficiency of SAMDC, and also that MdACL5 encodes a functional SPMS like as ACL5 in Arabidopsis. The first and second authors contributed equally to this work.

S-Adenosylmethionine decarboxylase

2009 ◽  
Vol 46 ◽  
pp. 25-46 ◽  
Author(s):  
Anthony E. Pegg
Keyword(s):  
Subunit Composition ◽  
Decarboxylase Activity ◽  
Primary Sequence ◽  
Prosthetic Group ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Decarboxylation Reaction ◽  
Key Enzyme ◽  
Covalently Bound

S-Adenosylmethionine decarboxylase is a key enzyme for the synthesis of polyamines in mammals, plants and many other species that use aminopropyltransferases for this pathway. It catalyses the formation of S-adenosyl-1-(methylthio)-3-propylamine (decarboxylated S-adenosylmethionine), which is used as the aminopropyl donor. This is the sole function of decarboxylated S-adenosylmethionine. Its content is therefore kept very low and is regulated by variation in the activity of S-adenosylmethionine decarboxylase according to the need for polyamine synthesis. All S-adenosylmethionine decarboxylases have a covalently bound pyruvate prosthetic group, which is essential for the decarboxylation reaction, and have similar structures, although they differ with respect to activation by cations, primary sequence and subunit composition. The present chapter describes these features, the mechanisms for autocatalytic generation of the pyruvate from a proenzyme precursor and for the decarboxylation reaction, and the available inhibitors of this enzyme, which have uses as anticancer and anti-trypanosomal agents. The intricate mechanisms for regulation of mammalian S-adenosylmethionine decarboxylase activity and content are also described.

scholarly journals Inhibition of the synthesis of polyamines and macromolecules by 5′-methylthioadenosine and 5′-alkylthiotubercidins in BHK21 cells

1982 ◽  
Vol 204 (3) ◽  
pp. 697-703 ◽  
Author(s):  
Aarne Raina ◽  
Kyllikki Tuomi ◽  
Raija-Leena Pajula
Keyword(s):  
Growth Inhibition ◽  
Spermidine Synthase ◽  
Baby Hamster Kidney ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Target Sites ◽  
Polyamine Content ◽  
Exogenous Spermidine

5′-Methylthioadenosine and four 5′-alkylthiotubercidins were tested for their ability to inhibit polyamine synthesis in vitro and to decrease polyamine concentration and prevent growth of baby-hamster-kidney (BHK21) cells. 5′-Methylthioadenosine and 5′-methylthiotubercidin decreased the activity of spermidine synthase from brain to roughly the same extent, whereas brain spermine synthase was much more strongly inhibited by 5′-methylthioadenosine compared with 5′-methylthiotubercidin. These nucleoside derivatives also inhibited the growth of BHK21 cells and increased the concentration of putrescine. 5′-Methylthioadenosine decreased cellular spermine concentration, whereas 5′-methylthiotubercidin lowered the concentration of spermidine. The activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase were enhanced in cells grown in the presence of 5′-methylthiotubercidin. The growth inhibition produced by these nucleoside derivatives was not reversed by exogenous spermidine or spermine. 5′-Ethylthiotubercidin, 5′-propylthiotubercidin and 5′-isopropylthiotubercidin did not appreciably inhibit spermidine or spermine synthase in vitro or decrease the cellular polyamine content, but effectively prevented the growth of BHK21 cells. All nucleoside derivatives at concentrations of 0.2–1 mm caused a rapid inhibition of protein synthesis. It is concluded that the growth inhibition produced by 5′-methylthioadenosine and 5′-alkylthiotubercidins was not primarily due to polyamine depletion but other target sites, for instance the cellular nucleotide pool, cell membranes etc. must be considered.

Regulation of polyamine content in cultured fibroblasts

1982 ◽  
Vol 243 (5) ◽  
pp. C262-C269 ◽  
Author(s):  
D. R. Bethell ◽  
H. Hibasami ◽  
A. E. Pegg
Keyword(s):  
Growth Period ◽  
Transformed Cells ◽  
Biosynthetic Enzymes ◽  
Spermidine Synthase ◽  
3T3 Cells ◽  
Cultured Fibroblasts ◽  
Mouse Fibroblasts ◽  
Adenosylmethionine Decarboxylase ◽  
Spermine Synthase ◽  
Polyamine Content

The content of putrescine and of the polyamines (spermidine and spermine) and the activities of their biosynthetic enzymes were measured in 3T3 mouse fibroblasts and SV40-transformed mouse fibroblasts over the entire period from subculturing in fresh medium until confluence. The transformed cells had a substantially higher content of putrescine and spermidine than the 3T3 cells and higher activities of all of the biosynthetic enzymes. However, the ratio of spermine synthase to spermidine synthase was higher in the 3T3 cells, which correlated with their higher spermine-to-spermidine ratio. All of the biosynthetic enzymes increased in activity during cell growth. Ornithine decarboxylase increased 20-fold with a maximum at 24-36 h after culturing whereas S-adenosylmethionine decarboxylase increased 3-fold at the same time. Spermidine synthase increased 10- to 16-fold during the growth period whereas spermine synthase increased 2- to 3-fold. The relative enzyme activities and the changes in total polyamine content suggested that 1) the activity of S-adenosylmethionine decarboxylase limited the production of the polyamines and 2) the relative amounts of spermidine and spermine synthase determined the predominant polyamine that the available decarboxylated S-adenosylmethionine is used to synthesize. When 3T3 cells become quiescent at confluence, there was a substantial fall in the intracellular spermidine level because of a greatly increased excretion of spermidine into the medium. Spermine content also fell because there was an increased conversion of spermine into spermidine, which was then excreted. The specific excretion of spermidine did not occur with the transformed SV-3T3 cells.

scholarly journals Overexpression of arginine decarboxylase in transgenic plants

1997 ◽  
Vol 325 (2) ◽  
pp. 331-337 ◽  
Author(s):  
Daniel BURTIN ◽  
Anthony J. MICHAEL
Keyword(s):  
Transgenic Plants ◽  
Arginine Decarboxylase ◽  
Polyamine Metabolism ◽  
Morphological Development ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Two Generations ◽  
Key Enzyme ◽  
Polyamine Conjugate ◽  
And Control

The activity of arginine decarboxylase (ADC), a key enzyme in plant polyamine biosynthesis, was manipulated in two generations of transgenic tobacco plants. Second-generation transgenic plants overexpressing an oat ADC cDNA contained high levels of oat ADC transcript relative to tobacco ADC, possessed elevated ADC enzyme activity and accumulated 10–20-fold more agmatine, the direct product of ADC. In the presence of high levels of the precursor agmatine, no increase in the levels of the polyamines putrescine, spermidine and spermine was detected in the transgenic plants. Similarly, the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase were unchanged. No diversion of polyamine metabolism into the hydroxycinnamic acid–polyamine conjugate pool or into the tobacco alkaloid nicotine was detected. Activity of the catabolic enzyme diamine oxidase was the same in transgenic and control plants. The elevated ADC activity and agmatine production were subjected to a metabolic/physical block preventing increased, i.e. deregulated, polyamine accumulation. Overaccumulation of agmatine in the transgenic plants did not affect morphological development.

Polyamine synthesis in liver and kidney of flounder in response to methylmercury

1976 ◽  
Vol 231 (2) ◽  
pp. 560-564 ◽  
Author(s):  
CA Manen ◽  
B Schmidt-Nielsen ◽  
DH Russell
Keyword(s):  
Ornithine Decarboxylase ◽  
Single Injection ◽  
Recovery Phase ◽  
Winter Flounder ◽  
Decarboxylase Activity ◽  
Pseudopleuronectes Americanus ◽  
Toxic Dose ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Liver And Kidney

The effect of methylmercury administration on polyamine synthesis was studied in the liver and kidney of the winter flounder (Pseudopleuronectes americanus). A single injection of methylmercury resulted in five- and sevenfold elevations of ornithine decarboxylase activity in the liver and kidney within 15 and 45 h, respectively. There were elevations of both putrescine- and spermidine-stimulated S-adenosylmethionine decarboxylase activities (approximately 1.5-fold) in both tissues. Evaluation of the polyamine accumulation patterns in these tissues indicated that in the liver all three polyamines increased in concentration until 48 h and then decline. In the kidney, the concentration of putrescine increased steadily until it was 200% of control at 72 h and then declined. Spermidine concentration decreased throughout the time studied and was 17% of control at 1 wk. There was no significant change in the concentration of spermine throughout the period studied. The changes in the polyamine pools and in the activities of the polyamine biosynthetic enzymes after methylmercury administration are consistent with an involvement of the polyamines in the recovery phase to a toxic dose of methylmercury.

Inhibitors Influencing Plant Enzymes of the Polyamine Biosynthetic Pathway

1989 ◽  
Vol 44 (1-2) ◽  
pp. 49-54 ◽  
Author(s):  
Marbeth Christ ◽  
Hansruedi Felix ◽  
Jost Harr
Keyword(s):  
Biosynthetic Pathway ◽  
Early Stage ◽  
Arginine Decarboxylase ◽  
Polyamine Biosynthesis ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Stage Of Development ◽  
Decarboxylase Inhibitors ◽  
Plant Enzymes ◽  
To Come

Absract Several enzymes involved in polyamine biosynthesis namely ornithine, arginine and S-adenosylmethionine decarboxylase as well as spermidine synthase, were analyzed in partially purified wheat extracts. For all enzymes effective inhibitors were found. Among them the most interesting was l-aminooxy-3-aminopropane, which inhibited all three decarboxylases. Classical polyamine biosynthesis inhibitors like difluoromethylornithine, difluoromethylarginine. methyl glyoxal bis- (guanylhydrazone) and cyclohexylamine were also inhibitory on plant enzymes. A remarkable difference in the amount of arginine and ornithine decarboxylase existed in wheat. Arginine decarboxylase seems to be more important at least during the early stage of development. Influence of polyamine synthesis inhibitors on polyamine levels is more likely to come from arginine decarboxylase inhibitors. As inhibitors of all essential enzymes involved in plant polyamine biosynthesis were found, the study of the importance of polyamines in plant physiology will be considerably facilitated.

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