Isolation and partial characterization of poly (A)-containing 7.5S messenger RNA from rat liver mitochondria

Poly(A)-containing low molecular weight (7.5S) messenger RNA was isolated in a highly purified form from both polyribosomes and post-polysomal. supernatant of rat liver mitochondria. Both mRRA's contain rather short poly(A) tracts (40–70 mononucleotides) according to a profile of their elution from poly(U)-Sepharose column with a gradient of formamide concentration. Both mRNA's when added to a preincubated. mitochondrial lysate programmed. the synthesis of a hydrophobic polypeptide of a molecular weight about 9000 daltona which was soluble in the neutral chloroform-methanol mixture.