Interleukin-2 induces a rapid increase in ornithine decarboxylase mRNA in a cloned murine T lymphocytic cell line.
We recently observed a 25-fold increase in the activity of ornithine decarboxylase (ODC) 6 h after treatment of G1-synchronized CTLL-2 cells with interleukin-2 (IL-2). Here we show that the ODC mRNA content increased in parallel with the ODC activity during the first hours of stimulation with IL-2, resulting in a 25-fold increase at 6 h. Between 6 and 24 h the ODC mRNA content continued to increase steadily up to 50-fold, even after the ODC activity had returned to low basal levels. In the case of density-arrested CTLL-2 cells deprived of IL-2 for 16 h, the IL-2-mediated increase in ODC mRNA was 2-fold at 1 h and 5-fold at 8 h, irrespective of the capability of the cells to resume their cycle. There was no marked increase in the rate of transcription of the ODC gene, at least during the first 2 h of stimulation with IL-2. These findings suggest that the regulation of the ODC activity by IL-2 is a primary event in IL-2-induced cell proliferation and occurs at the post-transcriptional level, possibly by stabilizing the ODC mRNA and affecting the efficiency of translation of the messenger.
Legraverend
C
C
Department of Pathology, University of Helsinki, Finland.
Potter
A
A
Hölttä
E
E
Alitalo
K
K
Andersson
L C
LC
D000818:Animals; D002452:Cell Count; D002455:Cell Division; D002999:Clone Cells; D005786:Gene Expression Regulation; D007376:Interleukin-2 / Q000494:pharmacology*; D051379:Mice; D009955:Ornithine Decarboxylase / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D014158:Transcription, Genetic
D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D009955:Ornithine Decarboxylase