Molecular cloning and characterization of the β-1,3-glucan recognition protein in Anatolica polita

beta-1,3-Glucan recognition protein (beta GRP) is an important pattern recognition protein, which could trigger immune response to eliminate pathogens by identifying and combining the pathogenic bacteria. In the present study, a beta-1,3-glucan recognition protein gene (Ap beta GRP) was cloned from a desert beetle Anatolica polita based on the EST sequence of Ap beta GRP in the suppression subtractive cDNA library. Quantitative real-time PCR (qRT-PCR) results showed that Ap beta GRP transcript in A. polita was significantly upregulated under the challenge of Escherichia coli and Staphylococcus aureus. Western blot analysis indicated that recombinant Ap beta GRP expressed in E. coli BL21, has the ability of binding to E. colt and S. aureus. Moreover, agglutination assay suggested that recombinant Ap beta GRP could agglutinate E. coli, S. aureus and Saccharomyces cerevisiae. The predicted 3D structure showed that Ap beta GRP possesses a typical beta-glucan recognition domain with seven beta-strands structures and conserved amino acid sequence. These data indicate that Ap beta GRP may be involved in immune defense in A. polita and could recognize and bind the bacteria against the invasion of external pathogens.