HIGHLY EFFICIENT DNA-SYNTHESIS IN ISOLATED-MITOCHONDRIA FROM RAT-LIVER

We have developed a highly efficient DNA-synthesizing system with isol ated intact rat liver mitochondria. The ATP requirements for this in o rganello DNA synthesis are provided by endogenous synthesis in the pre sence of exogenous ADP and an oxidizable substrate. In this system, mi tochondrial DNA synthesis strikingly proceeds at a constant rate for a bout 5 h at 37 degrees C. Gel electrophoresis, hybridization and restr iction enzyme analyses show that intact mitochondria synthesize nuclei c acids with a size of 16.5 kb, that correspond to mitochondrial DNA, and that both DNA strands are replicated. This in organello DNA synthe sis requires the supply of dNTPs and decreases at high ADP concentrati on in the incubation medium.