Inhibition of mitochondrial protein synthesis in regenerating rat liver stimulates mitochondrial transcription.
Partially hepatectomized rats were treated in vivo with thiamphenicol for 3 days to block mitochondrial protein synthesis. Protein synthesis, RNA synthesis and the steady-state levels of individual transcripts were measured in mitochondria in vitro in the absence of thiamphenicol. Incorporation of [35S]methionine and [3H]UTP into protein and RNA, respectively, was increased 2-3-fold in isolated mitochondria from thiamphenicol-treated animals, indicating increased rates of synthesis of both. Electrophoretic analysis of transcripts labelled with [32P]UTP suggests that synthesis of all the transcripts is increased. The steady-state concentrations of mitochondrial transcripts, measured by Northern blotting using nick-translated cloned EcoRI fragments of rat liver mtDNA, were also elevated 2-4-fold in thiamphenicol-treated animals. The data suggest that mitochondrial transcription is under control of a mitochondrial factor which, in turn, is dependent upon mitochondrial protein synthesis.
Kuzela
S
S
Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden.
Mutvei
A
A
Nelson
B D
BD
D000818:Animals; D015152:Blotting, Northern; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012313:RNA / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D013839:Thiamphenicol / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D014544:Uridine Triphosphate / Q000378:metabolism
D004272:DNA, Mitochondrial; D011500:Protein Synthesis Inhibitors; D012313:RNA; D008715:Methionine; D013839:Thiamphenicol; D014544:Uridine Triphosphate