title: Microsporidian polar tube proteins: highly divergent but closely linked genes encode PTP1 and PTP2 in members of the evolutionarily distant Antonospora and Encephalitozoon groups.
abstract: The spore polar tube is a unique organelle required for cell invasion by fungi-related microsporidian parasites. Two major polar tube proteins (PTP1 and PTP2) are encoded by two tandemly arranged genes in Encephalitozoon species. A look at Antonospora (Nosema) locustae contigs (http://jbpc.mbl.edu/Nosema/Contigs/) revealed significant conservation in the order and orientation of various genes, despite high sequence divergence features, when comparing with Encephalitozoon cuniculi complete genome. This syntenic relationship between distantly related Encephalitozoon and Antonospora genera has been successfully exploited to identify ptp1 and ptp2 genes in two insect-infecting species assigned to the Antonospora clade (A. locustae and Paranosema grylli). Targeting of respective proteins to the polar tube was demonstrated through immunolocalization experiments with antibodies raised against recombinant proteins. Both PTPs were extracted from spores with 100mM dithiothreitol. Evidence for PTP1 mannosylation was obtained in studied species, supporting a key role of PTP1 in interactions with host cell surface.
authors.affiliation: Equipe Parasitologie Moléculaire et Cellulaire, Laboratoire Biologie des Protistes, UMR CNRS 6023, Université Blaise Pascal, 24 Avenue des Landais 63177 Aubière Cedex, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Polonais
authors.forename: Gérard
authors.initials: G
authors.lastname: Prensier
authors.forename: Guy
authors.initials: G
authors.lastname: Méténier
authors.forename: Christian P
authors.initials: CP
authors.lastname: Vivarès
authors.forename: Frédéric
authors.initials: F
authors.lastname: Delbac
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016819:Encephalitozoon / Q000737:chemistry / Q000235:genetics*; D005656:Fungal Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D005800:Genes, Fungal; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D016814:Microsporidia / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D015388:Organelles / Q000235:genetics*; D021381:Protein Transport; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000737:chemistry; D026801:Synteny
chemical_list: D005656:Fungal Proteins