Molecular cloning and characterization of High Mobility Group box（HMGB）gene from Beauveria bassiana- infected silkworm, Bombyx mori

The cDNA sequence of High Mobility Group box (HMGB) from Bombyx mori was cloned by rapid amplification of cDNA ends and submitted to GenBank (the accession number was JF969272). The full-length cDNA of BmHMGB included 3015 bp, with five exons and four introns. It contained a 313 bp 5′ UTR, a 2114 bp 3′ UTR with a polyadenylation signal sequence AATAAA and a poly(A) tail. It encodes a 195- amino acid polypeptide with a predicted molecular weight about 22991.9Da and a theoretical isoelectric point 10.00. Phylogenetic analysis revealed that BmHMGB is grouped in insect HMGB proteins. BmHMGB was mainly expressed in hemolymph, cuticles, midgut and fat body by RT-PCR. In these tissues, the relative expression of BmHMGB with Beauveria bassiana infected silkworm was higher than the normal ones by fluorescent quantitative real-time PCR. Therefore, BmHMGB may play an important function in the response to B. bassiana infection of silkworms.