Mouse L cell mitochondrial DNA molecules are selected randomly for replication throughout the cell cycle.
The number of mitochondrial DNA molecules in a cell population doubles at the same rate as the cell generation time. This could occur by a random selection of molecules for replication or by a process that ensures the replication of each individual molecule in the cell. We have investigated the rate at which mouse L cell mitochondrial DNA molecules labeled with 3H-thymidine during one round of replication are reselected for a second round of replication. Mouse L cells were labeled with 3H-thymidine for 2 hr, chased for various periods of time and then labeled with 5-bromodeoxyuridine for 4 hr immediately before mitochondrial DNA isolation. A constant fraction of 3H-thymidine-labeled mitochondrial DNA incorporated 5-bromodeoxyuridine after chase intervals ranging from 1.5-22 hr. This result demonstrates that mitochondrial DNA molecules replicated in a short time interval are randomly selected for later rounds of replication, and that replication of mitochondrial DNA continues throughout the cell cycle in mouse L cells.
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002455:Cell Division; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000096:biosynthesis*; D007739:L Cells / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D013936:Thymidine / Q000378:metabolism
D004272:DNA, Mitochondrial; D001973:Bromodeoxyuridine; D013936:Thymidine