Microscopy and Microanalysis

Biological Applications

Whole Cell Cryo-Electron Tomography Suggests Mitochondria Divide by Budding

Guo-Bin Hu 

Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA

Abstract

Eukaryotes rely on mitochondrial division to guarantee that each new generation of cells acquires an adequate number of mitochondria. Mitochondrial division has long been thought to occur by binary fission and, more recently, evidence has supported the idea that binary fission is mediated by dynamin-related protein (Drp1) and the endoplasmic reticulum. However, studies to date have depended on fluorescence microscopy and conventional electron microscopy. Here, we utilize whole cell cryo-electron tomography to visualize mitochondrial division in frozen hydrated intact HeLa cells. We observe a large number of relatively small mitochondria protruding from and connected to large mitochondria or mitochondrial networks. Therefore, this study provides evidence that mitochondria divide by budding.

(Received September 11 2013)

(Accepted May 06 2014)

Key words

  • cryo-EM;
  • cryo-electron tomography;
  • mitochondrion;
  • mitochondrial division;
  • mitochondrial budding;
  • mitochondrial dynamics

Correspondence

Corresponding author. ghu@crystal.harvard.edu