题 目： Whole Cell Cryo-Electron Tomography reveals mitochondria divide by budding
报告人： Guobin Hu Ph.D.，Senior Cryo Microscopist
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School
Current: E.A. Fischione Instruments Inc.
Eukaryotes rely on mitochondrial division so that new generation of cells can acquire adequate number of mitochondria to maintain their physiological functions. Mitochondrial division has long been thought to occur by binary fission which has lately been considered to be mediated by Drp1 and ER. However, the visualization of mitochondrial division has depended heavily on the visualization by fluorescent microscopy and conventional electron microscopy (EM). The resolution limit of fluorescent microscopy (e.g. ~200 nm) is insufficient to visualize structural details of mitochondrial division. Specimen preparation in conventional EM, such as fixation, dehydration, staining and sectioning, could readily introduce artifacts. On the other hand, overlapping of three-dimensional (3D) structural information in two-dimensional (2D) images may result in the loss of contrast of fine structures in conventional EM. The Whole Cell Cryo-Electron Tomography which surmounts the shortcomings of fluorescent microscopy and conventional EM was utilized to visualize mitochondria in frozen hydrated intact cells. Three-dimensional tomography reconstructions showed a lot of mitochondrial budding, which resembles the reproductive budding of alpha-peoteobacteria. According to the genomics, mitochondria are evolved from ancient alpha-proteobacteria, which provides evolutionary support to the idea that mitochondrial divide by budding. Therefore, this study has revealed that mitochondria divide by budding.
Guobin Hu, Ph.D.
Ph.D. 2001, the Institute of Physics, Chinese Academy of Sciences
2002.7 – 2003. 6, University of Texas Houston Health Science Center
Project, Cryo-EM of human pyruvate dehydrogenase complex
2003.7 – 2005.11, Baylor College of Medicine & University of Texas Medical Branch.
Project, Cryo-EM of nematode body wall muscle thick filament core
2005.12 – 2008.11, New York University School of Medicine
Project 1, Cryo-electron tomography of bacteriophage Φ12
Project 2, Electron tomography of negatively stained tubular Kdp-ATPase crystals
Project 3, Cryo-EM of reconstituted 30-nm chromatin fiber
Project 4, Whole Cell Cryo-electron tomography of desmosome structure and assembling
2008.12 – 2012.7, Harvard Medical School
Project 1, Whole Cell Cryo-Electron Tomography of poliovirus cellular entry pathway
Project 2, Whole Cell Cryo-Electron Tomography of Mitochondria division
2012.9 – 2015.3, Senior Cryo-EM Applications Specialist, JEOL USA Inc.
2015.6 – present, Senior Cryo Microscopist, Fischione Instruments Inc.