Messenger ribonucleic acid metabolism in mammalian mitochondria. Discrete poly(adenylic acid) lacking messenger ribonucleic acid species associated with mitochondrial polysomes.
The mRNA species released from mitochondrial polysomes prepared by the Mg2+ precipitation technique have been further characterized using various analytical techniques. Mitochondrial polysomes were dissociated by treatment with puromycin and chemically labeled with (3H) dimethyl sulfate. About 51% of steady-state mitochondrial mRNA bind to oligo(dT)-cellulose indicating the presence of poly(adenylic acid)(poly(A)) in this fraction. The poly(A)-containing mRNAs resolve into discrete bands of 9-16 Se, while the RNA fraction unable to bind to oligo(dT)-cellulose representing poly(A)-lacking mRNA contains 8-12 Se species. About 90% of poly(A) lacking RNA hybridizes with mitochondrial DNA and less than 7% hybridizes with nuclear DNA. The extent of hybridization of poly(A)-lacking RNA with mitochondrial DNA was not significantly affected by the presence of excess mitochondrial rRNA, cytoplasmic rRNA, or a tenfold concentration of poly(A)-containing RNA isolated from total mitochondrial RNA. Possible differences in sequence properties between poly(A)-containing and -lacking mitochondrial mRNAs were further verified using a solid phase-bound cDNA procedure. Poly(A)-containing mRNA released from mitochondrial polysomes shows over 85% sequance homology with oligo(dT)-cellulose-bound cDNA prepared against total mitochondrial poly(A)-lacking mitochondrial mRNA hybridizes with the cDNA providing direct evidence for the distinct sequence properties of the two mRNA species.
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D011061:Poly A; D011132:Polyribosomes / Q000378:metabolism*; D011691:Puromycin; D012333:RNA, Messenger / Q000378:metabolism*
D012333:RNA, Messenger; D011061:Poly A; D011691:Puromycin