Human liver mitochondrial RNA synthesized in isolated organelles

The study of alterations of mitochondrial DNA transcription could be of fundamental interest to understand the molecular mechanisms underlying the impairment of mitochondrial function in liver diseases related to hepatocyte energy production. We show that isolated normal human liver mitochondria, when incubated in the presence of [α-³²P]UTP in an appropriate incubation medium, in which the energy requirements are provided by exogenous ADP in the presence of oxidizable substrates, are able to support RNA synthesis in a way faithfully resembling the in vivo process. The autoradiographic pattern in agarosemethylmercury hydroxide gels of the newly synthesized RNA shows the presence of all the previously described RNAs coded in the mitochondrial genome (ribosomal, messenger and transfer RNAs). We conclude that this system could be of great value to investigate the role of the mitochondrial genome on human liver pathology related to mitochondrial damage.