Replication of Mouse L-cell Mitochondrial DNA

  1. D. Bogenhagen,
  2. A. M. Gillum,
  3. P. A. Martens, and
  4. D. A. Clayton
  1. Laboratory of Experimental Oncology, Department of Pathology, Stanford University School of Medicine, Stanford, California 94305

This extract was created in the absence of an abstract.

Excerpt

Mitochondrial DNA (mtDNA) of mouse L cells employs a very distinctive replication mechanism, termed asynchronous displacement replication, which was proposed several years ago on the basis of electron microscopic analyses of replicating molecules (Kasamatsu et al. 1971; Robberson et al. 1972; Kasamatsu and Vinograd 1973; reviewed by Kasamatsu et al. 1974 and Kasamatsu and Vinograd 1974). Subsequent pulse-chase labeling experiments in our laboratory have corroborated and refined this model. These studies have revealed a marked asynchrony in the synthesis of the two complementary strands of mtDNA, which are separable into a heavy (H) and a light (L) strand by equilibrium centrifugation in alkaline CsCl gradients.

In mouse L cells, up to 70% of the mtDNA molecules contain a partially replicated region at the H-strand replication origin, termed a displacement loop (D loop) (Kasamatsu et al. 1971). This triple-stranded structure is created by synthesis of 500–600 nucleotides of the H strand,...

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