Increased mitochondrial-encoded gene transcription in immortal DF-1 cells.
We have established, in continuous cell culture, a spontaneously immortalized chicken embryo fibroblast (CEF) cell line (DF-1) as well as several other immortal CEF cell lines. The immortal DF-1 cells divided more rapidly than primary and other immortal CEF cells. To identify the genes involved in rapidly dividing DF-1 cells, we have used differential display RT-PCR. Of the numerous genes analyzed, three mitochondrial-encoded genes (ATPase 8/6, 16S rRNA, and cytochrome b) were shown to express at higher levels in DF-1 cells compared to primary and other immortal CEF cells. The inhibition of mitochondrial translation by treatment with chloramphenicol markedly decreased ATP production and cell proliferation in DF-1 cells, while not affecting growth in either primary or other immortal CEF cells. This result suggests a correlation between rapid cell proliferation and the increased mitochondrial respiratory functions. We also determined that the increased transcription of mitochondrial-encoded genes in DF-1 cells is due to increased de novo transcript synthesis as shown by mitochondrial run-on assays, and not the result of either increased mitochondrial biogenesis or mitochondrial transcript half-lives. Together, the present studies suggest that the transcriptional activation of mitochondrial-encoded genes and the elevated respiratory function should be one of the characteristics of rapidly dividing immortal cells.
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Department of Animal Science, University of Minnesota, St. Paul, Minnesota 55108, USA.
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Farris
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Foster
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Foster
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002461:Cell Line, Transformed; D002642:Chick Embryo; D002701:Chloramphenicol / Q000494:pharmacology; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D003609:Dactinomycin / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics; D008928:Mitochondria / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D014158:Transcription, Genetic
D004272:DNA, Mitochondrial; D011500:Protein Synthesis Inhibitors; D003609:Dactinomycin; D002701:Chloramphenicol; D000255:Adenosine Triphosphate