a broad distribution of the alternative oxidase in microsporidian parasites广泛分布的替代氧化酶microsporidian寄生虫.pdfVIP

A Broad Distribution of the Alternative Oxidase in Microsporidian Parasites 1,2 3 2 4 4 Bryony A. P. Williams , Catherine Elliot , Lena Burri , Yasutoshi Kido , Kiyoshi Kita , Anthony L. 3 2 Moore , Patrick J. Keeling * 1 School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, Devon, United Kingdom, 2 Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada, 3 Department of Biochemistry and Biomedical Sciences, School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom, 4 Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Tokyo, Japan Abstract Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of iron- sulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidia and their mitosomes are anaerobic, as is the case for other mitosome bearing eukaryotes, such as Giardia. Here we provide evidence opening the possibility that mitosomes in a number of microsporidian lineages are not completely anaerobic. Specifically, we have identified and characterized a gene encoding the alternative oxidase (AOX), a typically mitochondrial terminal oxidase in eukaryotes, in the genomes of several distantly related microsporidian species, even though this