title: The thrombospondin-related protein CpMIC1 (CpTSP8) belongs to the repertoire of micronemal proteins of Cryptosporidium parvum.
abstract: Bioinformatic data show that, in addition to TRAP-C1, Cryptosporidium parvum encodes 11 thrombospondin-related proteins (CpTSP2 through CpTSP12), none of which has been characterized yet. We describe herein the cloning of a 2048 bp-long sporozoite cDNA encoding CpTSP8, a type I integral membrane protein of 614 amino acids, possessing three thrombospondin type I (TSP1) repeats and one epidermal growth factor (EGF)-like domain. Transcriptionally, CpTSP8 is represented by a fully spliced and two immature mRNA forms, in which the intron is either totally or partially retained. Immunofluorescence analysis detected CpTSP8 in the apical complex of both sporozoites and type I merozoites, and showed that, upon sporozoite exposure to host cells in vitro, the protein is translocated onto the parasite surface as typical of micronemal proteins (MICs). Accordingly, double immunofluorescence localized CpTSP8 to C. parvum micronemes, prompting us to rename it CpMIC1 in agreement with the current MICs nomenclature.
authors.affiliation: Unit of Microbiology and Virology, Children's Hospital and Research Institute Bambino Gesù, Piazza S. Onofrio 4, 00165 Rome, Italy.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Putignani
authors.forename: Alessia
authors.initials: A
authors.lastname: Possenti
authors.forename: Simona
authors.initials: S
authors.lastname: Cherchi
authors.forename: Edoardo
authors.initials: E
authors.lastname: Pozio
authors.forename: Andrea
authors.initials: A
authors.lastname: Crisanti
authors.forename: Furio
authors.initials: F
authors.lastname: Spano
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000737:chemistry; D003001:Cloning, Molecular; D016785:Cryptosporidium parvum / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D007438:Introns; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D019699:Thrombospondins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D008565:Membrane Proteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D019699:Thrombospondins