Mitochondrial DNA molecules and virtual number of mitochondria per cell in mammalian cells

TLDR

The authors developed a biochemical method using a plasmid probe to estimate the virtual number of mitochondria per cell and measure mt DNA per mitochondrion and per cell, applying it to five cell types from four mammalian species. The study found that mt DNA per mitochondrion is essentially constant (~2.6 molecules), while mt DNA per cell and virtual mitochondria per cell vary eightfold across five mammalian cell types (220–1,720 mt DNA molecules/cell and 83–677 virtual mitochondria/cell), with each virtual mitochondrion carrying the same genomic mass and numbers tightly regulated within a cell type but differing widely between types.

Abstract

Abstract A new biochemical method for estimating the virtual number of mitochondria (mt) per cell was developed and used together with a plasmid probe to measure mt DNA/mitochondrion and mt DNA/cell. These methods were used in five cell types from four mammalian species. Mt DNA/mitochondrion was essentially constant in all cell types (mean 2.6 ± 0.30 SE mitochondrial DNA molecules/mt). Mt DNA molecules/cell encompassed an eight‐fold range between various cell types (low 220 ± 6.2; high 1,720 ± 162 mt DNA molecules/cell). Virtual mt number/cell ranged from 83 ± 17 to 677 ± 80 (SE) mt/cell in various cell types. All five mammalian virtual mitochondria contained the same genomic mass. The number of virtual mitochondria per cell and amount of mt DNA per cell appear to be closely regulated within a given cell type but differ widely from cell type to cell type.