Mouse L cell mitochondrial DNA molecules are selected randomly for replication throughout the cell cycle

Cell. 1977 Aug;11(4):719-27. doi: 10.1016/0092-8674(77)90286-0.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bromodeoxyuridine / metabolism
  • Cell Division
  • DNA Replication*
  • DNA, Mitochondrial / biosynthesis*
  • L Cells / metabolism*
  • Mice
  • Models, Biological
  • Thymidine / metabolism


  • DNA, Mitochondrial
  • Bromodeoxyuridine
  • Thymidine