title: Identification of two new polar tube proteins related to polar tube protein 2 in the microsporidian Antonospora locustae.
abstract: Microsporidia are obligate intracellular eukaryotic parasites with a broad host spectrum characterized by a unique and highly sophisticated invasion apparatus, the polar tube (PT). In a previous study, two PT proteins, named AlPTP1 (50 kDa) and AlPTP2 (35 kDa), were identified in Antonospora locustae, an orthoptera parasite that is used as a biological control agent against locusts. Antibodies raised against AlPTP2 cross-reacted with a band migrating at ~70 kDa, suggesting that this 70-kDa antigen is closely related to AlPTP2. A blastp search against the A. locustae genome database allowed the identification of two further PTP2-like proteins named AlPTP2b (568 aa) and AlPTP2c (599 aa). Both proteins are characterized by a specific serine- and glycine-rich N-terminal extension with elastomeric structural features and share a common C-terminal end conserved with AlPTP2 (~88% identity for the last 250 aa). MS analysis of the 70-kDa band revealed the presence of AlPTP2b. Specific anti-AlPTP2b antibodies labelled the extruded PTs of the A. locustae spores, confirming that this antigen is a PT component. Finally, we showed that several PTP2-like proteins are also present in other phylogenetically related insect microsporidia, including Anncaliia algerae and Paranosema grylli.
authors.affiliation: Clermont Université, Université d'Auvergne, Laboratoire Microorganismes: Génome et Environnement, Clermont-ferrand, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Polonais
authors.forename: Abdel
authors.initials: A
authors.lastname: Belkorchia
authors.forename: Michaël
authors.initials: M
authors.lastname: Roussel
authors.forename: Eric
authors.initials: E
authors.lastname: Peyretaillade
authors.forename: Pierre
authors.initials: P
authors.lastname: Peyret
authors.forename: Marie
authors.initials: M
authors.lastname: Diogon
authors.forename: Frédéric
authors.initials: F
authors.lastname: Delbac
mesh_terms: D000908:Antibodies, Fungal / Q000276:immunology; D019295:Computational Biology; D003429:Cross Reactions; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000276:immunology; D013058:Mass Spectrometry; D016814:Microsporidia / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D000908:Antibodies, Fungal; D004271:DNA, Fungal; D005656:Fungal Proteins
keywords: Antonospora locustae; Microsporidia; elastomeric protein; invasion; polar tube