Eimeripain, a cathepsin b-like cysteine protease, expressed throughout sporulation of the apicomplexan parasite Eimeria tenella

Rieux, Anaïs, Gras, Simon, Lecaille, Fabien, Niepceron, Alisson, Katrib, Marilyn, Smith, Nicholas C., Lalmanach, Gilles, and Brossier, Fabien (2012) Eimeripain, a cathepsin b-like cysteine protease, expressed throughout sporulation of the apicomplexan parasite Eimeria tenella. PLoS ONE, 7 (3). e31914. pp. 1-11.

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Abstract

The invasion and replication of Eimeria tenella in the chicken intestine is responsible for avian coccidiosis, a disease that has major economic impacts on poultry industries worldwide. E. tenella is transmitted to naïve animals via shed unsporulated oocysts that need contact with air and humidity to form the infectious sporulated oocysts, which contain the first invasive form of the parasite, the sporozoite. Cysteine proteases (CPs) are major virulence factors expressed by protozoa. In this study, we show that E. tenella expresses five transcriptionally regulated genes encoding one cathepsin L, one cathepsin B and three cathepsin Cs. Biot-LC-LVG-CHN2, a cystatin derived probe, tagged eight polypeptides in unsporulated oocysts but only one in sporulated oocysts. CP-dependant activities were found against the fluorescent substrates, Z-FR-AMC and Z-LR-AMC, throughout the sporulation process. These activities corresponded to a cathepsin B-like enzyme since they were inhibited by CA-074, a specific cathepsin B inhibitor. A 3D model of the catalytic domain of the cathepsin B-like protease, based on its sequence homology with human cathepsin B, further confirmed its classification as a papain-like protease with similar characteristics to toxopain-1 from the related apicomplexan parasite, Toxoplasma gondii; we have, therefore, named the E. tenella cathepsin B, eimeripain. Following stable transfection of E. tenella sporozoites with a plasmid allowing the expression of eimeripain fused to the fluorescent protein mCherry, we demonstrated that eimeripain is detected throughout sporulation and has a punctate distribution in the bodies of extra- and intracellular parasites. Furthermore, CA-074 Me, the membrane-permeable derivative of CA-074, impairs invasion of epithelial MDBK cells by E. tenella sporozoites. This study represents the first characterization of CPs expressed by a parasite from the Eimeria genus. Moreover, it emphasizes the role of CPs in transmission and dissemination of exogenous stages of apicomplexan parasites.

Item ID: 22682
Item Type: Article (Research - C1)
ISSN: 1932-6203
Date Deposited: 01 Aug 2012 09:49
FoR Codes: 06 BIOLOGICAL SCIENCES > 0601 Biochemistry and Cell Biology > 060107 Enzymes @ 40%
06 BIOLOGICAL SCIENCES > 0605 Microbiology > 060502 Infectious Agents @ 30%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070708 Veterinary Parasitology @ 30%
SEO Codes: 93 EDUCATION AND TRAINING > 9399 Other Education and Training > 939999 Education and Training not elsewhere classified @ 60%
83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8303 Livestock Raising > 830309 Poultry @ 40%
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