Polyamine-mediated control of mammalian S-adenosyl-L-methionine decarboxylase expression: effects on the content and translational efficiency of the mRNA.
The expression of mammalian AdoMet decarboxylase, a key enzyme in polyamine synthesis, was shown to be regulated by polyamines at two different levels. Polyamine depletion of Ehrlich ascites tumor cells induced a marked compensatory increase in the synthesis of the enzyme, as measured by 35S-methionine pulse-labeling and immuno-precipitation. This increase in synthesis rate was counteracted by provision of spermidine, which reduced the synthesis of AdoMet decarboxylase to an undetectable level. Northern analysis revealed a nearly 2-fold increase in the amount of AdoMet decarboxylase mRNA when the putrescine and spermidine content was depleted. This increase in AdoMet decarboxylase mRNA content cannot account for the more than 5-fold increase in synthesis rate, indicating a feedback regulation also at the level of mRNA translation.
Persson
L
L
Department of Physiology, University of Lund, Sweden.
Stjernborg
L
L
Holm
I
I
Heby
O
O
D012437:Adenosylmethionine Decarboxylase / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D002262:Carboxy-Lyases / Q000235:genetics*; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology; D000518:Eflornithine / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation / Q000187:drug effects*; D007163:Immunosorbent Techniques; D009693:Nucleic Acid Hybridization; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D011700:Putrescine / Q000378:metabolism / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics*; D013095:Spermidine / Q000378:metabolism / Q000494:pharmacology
D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D012333:RNA, Messenger; D002262:Carboxy-Lyases; D012437:Adenosylmethionine Decarboxylase; D013095:Spermidine; D011700:Putrescine; D000518:Eflornithine