title: A Eukaryote without a Mitochondrial Organelle.
abstract: The presence of mitochondria and related organelles in every studied eukaryote supports the view that mitochondria are essential cellular components. Here, we report the genome sequence of a microbial eukaryote, the oxymonad Monocercomonoides sp., which revealed that this organism lacks all hallmark mitochondrial proteins. Crucially, the mitochondrial iron-sulfur cluster assembly pathway, thought to be conserved in virtually all eukaryotic cells, has been replaced by a cytosolic sulfur mobilization system (SUF) acquired by lateral gene transfer from bacteria. In the context of eukaryotic phylogeny, our data suggest that Monocercomonoides is not primitively amitochondrial but has lost the mitochondrion secondarily. This is the first example of a eukaryote lacking any form of a mitochondrion, demonstrating that this organelle is not absolutely essential for the viability of a eukaryotic cell.
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic; Department of Molecular Phylogenetics and Evolution, University of Warsaw, Warsaw 00478, Poland. Electronic address: ankarn@biol.uw.edu.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Karnkowska
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Vacek
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Zubáčová
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Sebastian C
authors.initials: SC
authors.lastname: Treitli
authors.affiliation: Department of Biology and Ecology, University of Ostrava, Ostrava 710 00, Czech Republic.
authors.forename: Romana
authors.initials: R
authors.lastname: Petrželková
authors.affiliation: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Eme
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Lukáš
authors.initials: L
authors.lastname: Novák
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Žárský
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Lael D
authors.initials: LD
authors.lastname: Barlow
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Emily K
authors.initials: EK
authors.lastname: Herman
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Soukal
authors.affiliation: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic.
authors.forename: Miluše
authors.initials: M
authors.lastname: Hroudová
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Doležal
authors.affiliation: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
authors.forename: Courtney W
authors.initials: CW
authors.lastname: Stairs
authors.affiliation: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Roger
authors.affiliation: Department of Biology and Ecology, University of Ostrava, Ostrava 710 00, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Eliáš
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Joel B
authors.initials: JB
authors.lastname: Dacks
authors.affiliation: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic.
authors.forename: Čestmír
authors.initials: Č
authors.lastname: Vlček
authors.affiliation: Department of Parasitology, Charles University in Prague, Prague 12843, Czech Republic. Electronic address: vlada@natur.cuni.cz.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Hampl
mesh_terms: D005075:Biological Evolution; D003600:Cytosol / Q000378:metabolism; D008928:Mitochondria / Q000502:physiology*; D056899:Oxymonadida / Q000166:cytology* / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D013455:Sulfur / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D013455:Sulfur