Lowered level of translatable messenger RNAs for manganese superoxide dismutase in human fibroblasts transformed by SV 40.
The activity of manganese superoxide dismutase (MnSOD) revealed by specific staining after gel electrophoresis of cell extracts, is decreased in human fibroblasts transformed by SV40. The decrease in enzyme activity is attributable to decreased amount of enzyme protein as determined by radial immunodiffusion. Total fibroblast RNAs were translated in the presence of (35S) methionine in a cell-free translation system and the neo synthesized proteins submitted to immunoprecipitation with an anti MnSOD antiserum. Gel electrophoresis of the immunoprecipitated material followed by fluorography shows that MnSOD is translated as a peptide which is 2000 daltons larger than the mature enzyme subunit. This precursor (pre-MnSOD) is processed in vitro to mature MnSOD by the action of an isolated mitochondrial preparation. Levels of translatable MnSOD mRNA in normal and SV 40 transformed cells were compared in terms of the radioactivities incorporated into pre MnSOD bands. The results indicate that the decreased amount of MnSOD in SV 40 transformed fibroblasts is due to a decreased level of translatable mRNA for MnSOD.
Marlhens
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Nicole
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Sinet
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D002472:Cell Transformation, Viral; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D005779:Immunodiffusion; D008099:Liver / Q000201:enzymology; D008345:Manganese / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D013539:Simian virus 40; D013482:Superoxide Dismutase / Q000235:genetics*
D012333:RNA, Messenger; D008345:Manganese; D013482:Superoxide Dismutase