title: Localization of eimeripain, an Eimeria tenella cathepsin B-like cysteine protease, during asexual and sexual intracellular development in chicken ceca.
abstract: Hemorrhagic diarrhea in poultry is caused by Eimeria tenella, the most pathogenic avian coccidian parasite, and new approaches to treat the disease are continually being sought. Although eimeripain, a cathepsin B-like cysteine protease from E. tenella, has recently been identified as a novel anticoccidial drug target, its localization during the intracellular development of parasites remains unclear. Here, we demonstrate the expression of eimeripain during asexual and sexual development of E. tenella in vivo. Promature eimeripain was detected only in the early immature second generation of schizonts. In contrast, the mature eimeripain was most strongly detected in the middle-sized immature second generation of schizonts. Both promature and mature eimeripain disappeared depending on the maturation level of second generation of schizonts, but were strongly expressed again in the third generation of schizonts. In the sexual stage, both promature and mature eimeripain were detected in the cytoplasm of micro- and macro-gametocytes and zygotes, but expression became weak in zoites forming oocysts. Collectively, our findings suggest that eimeripain might play a key role in the differentiation of intracellular zoites in the ceca and could be an interesting candidate to develop a novel, effective anti-coccidian drug.
authors.affiliation: National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsubayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hatta
authors.forename: Takeharu
authors.initials: T
authors.lastname: Miyoshi
authors.lastname: Anisuzzaman
authors.forename: Kazumi
authors.initials: K
authors.lastname: Sasai
authors.forename: Kayoko
authors.initials: K
authors.lastname: Yamaji
authors.forename: Kameo
authors.initials: K
authors.lastname: Shimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Isobe
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kita
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Tsuji
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western / Q000662:veterinary; D002432:Cecum / Q000469:parasitology*; D002645:Chickens; D003048:Coccidiosis / Q000662:veterinary*; D057056:Cysteine Proteases / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D003967:Diarrhea / Q000469:parasitology / Q000662:veterinary*; D016503:Drug Delivery Systems / Q000379:methods / Q000662:veterinary; D016786:Eimeria tenella / Q000254:growth & development*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D011201:Poultry Diseases / Q000469:parasitology*; D012098:Reproduction / Q000502:physiology; D017422:Sequence Analysis, DNA / Q000662:veterinary; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D037521:Virulence Factors; D057056:Cysteine Proteases; C574014:eimeripain protein, Eimeria tenella