Cloning, Expression, and Purification of a Pathogenesis-Related Protein from Oenanthe javanica and Its Biological Properties

Abstract

Pathogenesis-related (PR) proteins are inducible and accumulated in plants upon pathogen challenge for survival. Interest in these proteins has arisen in many fields of research, including areas of protein defense mechanisms and plant-derived allergens. In this study, we cloned a PR protein gene (OJPR) from Oenanthe javanica, which consisted of 465 bp with an approximate molecular mass of 16kDa. The DNA and deduced amino acid sequences of OJPR were 87% similar to Pimpinella brachycarpa PR-1 together with a glycine-rich loop which is a signature motif of PR-10. In microarray analysis, OJPR-transfected Raw264.7 (OJPR(+)) upregulated high mobility group box 1 and protein kinase C alpha, and downregulated chemokine ligand 3 and interleukin 1 beta which are all related to toll-like receptor 4 (TLR4) and inflammation. TAK-242 and PD98059 inhibited the activation by OJPR, suggesting that OJPR transduce TLR4-mediated signaling. Interestingly, OJPR increased anti-viral repertoires, including interferon (IFN)alpha, IFN gamma, OAS1, and Mx1 in CD4(+) primary T cells. Taken together, we concluded that OJPR may play a role in modulating host defense responses via TLR signal transduction and provide new insights into the therapeutic and diagnostic advantages as a potential bioactive protein.