Abstract: An 852 bp cDNA fragment was amplified by RT-PCR from total mRNA of the American cockroach, Periplaneta Americana (South China population) with a pair of primers that were designed according to the published tropomyosin gene. Sequence analysis indicated that three nucleotides changed in the gene compared with the reported Per a7 gene. The fragment was cloned into expression vector pET24a(+) and subsequently expressed in E. coli BL21 Star. SDS-PAGE analysis showed that the molecular weight of the expressed product was 33 kD. Western blotting indicated that the recombinant protein could combine with sera IgE from human individuals allergic to cockroach allergens.

Key words: Periplaneta americana, allergen, tropomyosin, Per a7 gene, immunological identification