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

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