Cloning of a Family of Serine Protease Genes Expressed in German Cockroach(Blattella germanica) and Possibility as Allergens / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: The serine protease allergens have been known as one of the most important inhalent allergens of insects as well as house dust mites. There is no known serine protease allergen of German cockroach, which is a well-known etiological agent of allergic diseases. We identified the serine protease genes of cockroach, Blattella germanica, and examined its possibility as an allergen. MATERIALS AND METHOD: We have isolated three partial genes, Bg3, Bg5 and Bg6, of serine protease from the Blattella germanica cDNA library using the degenerate oligonucleotide PCR primers specific for the conserved regions. RESULTS: The genes, Bg3, Bg5 and Bg6, were composed of 396 bp 131 amino acids, 513 bp 170 amino acids, and 410 bp 136 amino acids, respectively. Northern hybridization analysis indicated that the size of Bg5 and Bg6 transcripts was approximately 0.7 kb. The gene, Bg5, was also identified as a multiple gene by the Southern blot analysis. The gene, Bg3, showed significant homology to trypsin-like serine protease of various insects. The deduced amino acids sequence of the gene Bg5 was matched to the mite group III allergen as well as various species of insect serine protease sequences. The gene Bg6 also showed high homology to the amino acids sequences of insect serine proteases and mite group III allergens. Three Blattella germanica serine protease gene fragments revealed close genetic relationships with Dermatophagoides farinae group III allergen in the phylogenetic analysis. CONCLUSION: The high homology and close phylogenetic relationship raise the possibility of three serine protease genes as being an allergen of German cockroach.