Barbieri, Rosario , Remacle, Claire , Hamel, Patrice .
A candidate assembly of mitochondrial complex I (amc1) mutant in the green alga Chlamydomonas reinhardtii.
Cellular respiration is a central, overall conserved metabolic process that couples the electron transport from NADH to oxygen through a chain of membrane located complexes (I to IV) to the synthesis of ATP by the ATP synthase complex (complex V). Eukaryotic electron transport occurs at the mitochondrial inner membrane. Failure to assemble any of these complexes results in severe defects affecting cellular and organism viability, e.g. human Leigh’s syndrome. NADH dehydrogenase (Complex I) is the first complex in the system and, despite the presence of alternative dehydrogenases in plant mitochondria, its absence or defective assembly results in severe phenotypes, e.g. gametophyte abortion and altered photosynthetic performance. In our laboratory, we are using the green alga Chlamydomonas reinhardii as a model to decipher the molecular basis of mitochondrial complex I deficiency. C. reinhardtii complex I is formed by more than 40 proteins, 14 of which, the “core complex”, are common to all organisms, whereas the rest constitute accessory proteins with potential regulatory or assembly roles. Of these accessory proteins, 12 subunits are plant-specific. C. reinhardtii is able to grow either autotrophically in the light, or heterotrophically on acetate in the dark. Thus, mitochondrial mutants are conditional and can be propagated in the light. To identify genes involved in Complex I assembly, we generated a C. reinhardtii mutant insertion library and screened specifically for mutants growing slowly in the dark, a phenotypic trait of complex I-less mutants. Here, we describe the molecular and biochemical characterization of one these mutants, amc1 (for assembly of mitochondrial complex I), a candidate complex I assembly mutant, which is unable to form a functional Complex I.
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1 - The Ohio State University, Plant Cellular and Molecular Biology, 500 Aronoff Laboratory Building, 318 West 12th Ave, Columbus, Ohio, 43201, USA
2 - Université de Liège, Génétique des Microorganismes, Département des Sciences de la Vie, Institut de Botanique B22, Université de Liège, Liège, Belgium, B-4000, Belgium
3 - The Ohio State University, Department of Plant Cellular and Molecular Biology and Department of Molecular and Cellular Biochemistry, 500 Aronoff Laboratory Building, 318 West 12th Ave, Columbus, Ohio, 43201, USA
mitochondrial Complex I
mitochondrial electron transport
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM