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Functional characterization of SjB10, an intracellular serpin from Schistosoma japonicum

Published online by Cambridge University Press:  19 August 2014

ADEBAYO J. MOLEHIN ,
GEOFFREY N. GOBERT ,
PATRICK DRIGUEZ  and
DONALD P. MCMANUS
ADEBAYO J. MOLEHIN*
Affiliation:
Molecular Parasitology Laboratory, Department of Biology, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Australia 4006 School of Population Health, The University of Queensland, 300 Herston Road, Herston, Australia 4006
GEOFFREY N. GOBERT
Affiliation:
Molecular Parasitology Laboratory, Department of Biology, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Australia 4006
PATRICK DRIGUEZ
Affiliation:
Molecular Parasitology Laboratory, Department of Biology, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Australia 4006
DONALD P. MCMANUS
Affiliation:
Molecular Parasitology Laboratory, Department of Biology, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Australia 4006
*
*Corresponding author: Molecular Parasitology Laboratory, Department of Biology, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Queensland, Australia 4006. E-mail: adebayo.molehin@qimrberghofer.edu.au; ajmolehin@yahoo.com
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Summary

Serine protease inhibitors (serpin) play essential roles in many organisms. Mammalian serpins regulate the blood coagulation, fibrinolysis, inflammation and complement activation pathways. In parasitic helminths, serpins are less well characterized, but may also be involved in evasion of the host immune response. In this study, a Schistosoma japonicum serpin (SjB10), containing a 1212 bp open reading frame (ORF), was cloned, expressed and functionally characterized. Sequence analysis, comparative modelling and structural-based alignment revealed that SjB10 contains the essential structural motifs and consensus secondary structures of inhibitory serpins. Transcriptional profiling demonstrated that SjB10 is expressed in adult males, schistosomula and eggs but particularly in the cercariae, suggesting a possible role in cercarial penetration of mammalian host skin. Recombinant SjB10 (rSjB10) inhibited pancreatic elastase (PE) in a dose-dependent manner. rSjB10 was recognized strongly by experimentally infected rat sera indicating that native SjB10 is released into host tissue and induces an immune response. By immunochemistry, SjB10 localized in the S. japonicum adult foregut and extra-embryonic layer of the egg. This study provides a comprehensive demonstration of sequence and structural-based analysis of a functional S. japonicum serpin. Furthermore, our findings suggest that SjB10 may be associated with important functional roles in S. japonicum particularly in host-parasite interactions.

Keywords

Schistosoma japonicumserine protease inhibitorsSjB10structure-to-function analysisfunctional characterization
Type
Research Article
Information
Parasitology , Volume 141 , Issue 13 , November 2014 , pp. 1746 - 1760
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Copyright
Copyright © Cambridge University Press 2014 

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