BACKGROUND: Of the ten recognised groups of Dermatophagoides pteronyssinus allergens, the group 4 is the only group that has not been characterised at the molecular level. METHODS: Primers were designed to PCR amplify Der p 4 (D. pteronyssinus) and Eur m 4 (Euroglyphus maynei) cDNA. These fragments were used to screen the corresponding cDNA libraries and the cDNA clones obtained were subsequently sequenced. The coding regions of Der p 4 and Eur m 4 were cloned into the pET expression vector and recombinant histidine-tagged proteins expressed in Escherichia coli. RESULTS: cDNA clones which included the mature protein coding sequence for Der p 4 and Eur m 4 were sequenced. The Der p 4 and Eur m 4 genes were found to code for 496 amino acid mature proteins with residues important for the function of alpha-amylase highly conserved. Der p 4 and Eur m 4 were calculated to be 90% identical and a BLAST search of the GenBank database found these sequences to be approximately 50% identical to insect and mammalian alpha-amylases. The calculated molecular weights of Der p 4 and Eur m 4 were approximately 57,000, although recombinant Der p 4 and Eur m 4 migrate on SDS-PAGE at about 60,000. Der p 4 recombinant protein was found to bind specific IgE in 3 of the 10 house dust mite allergic patients tested. CONCLUSIONS: This paper describes the first cDNA sequence of Der p 4 and Eur m 4 confirming that this allergen is house dust mite alpha-amylase.
BACKGROUND: Of the ten recognised groups of Dermatophagoides pteronyssinus allergens, the group 4 is the only group that has not been characterised at the molecular level. METHODS: Primers were designed to PCR amplify Der p 4 (D. pteronyssinus) and Eur m 4 (Euroglyphus maynei) cDNA. These fragments were used to screen the corresponding cDNA libraries and the cDNA clones obtained were subsequently sequenced. The coding regions of Der p 4 and Eur m 4 were cloned into the pET expression vector and recombinant histidine-tagged proteins expressed in Escherichia coli. RESULTS: cDNA clones which included the mature protein coding sequence for Der p 4 and Eur m 4 were sequenced. The Der p 4 and Eur m 4 genes were found to code for 496 amino acid mature proteins with residues important for the function of alpha-amylase highly conserved. Der p 4 and Eur m 4 were calculated to be 90% identical and a BLAST search of the GenBank database found these sequences to be approximately 50% identical to insect and mammalian alpha-amylases. The calculated molecular weights of Der p 4 and Eur m 4 were approximately 57,000, although recombinant Der p 4 and Eur m 4 migrate on SDS-PAGE at about 60,000. Der p 4 recombinant protein was found to bind specific IgE in 3 of the 10 house dust mite allergicpatients tested. CONCLUSIONS: This paper describes the first cDNA sequence of Der p 4 and Eur m 4 confirming that this allergen is house dust mite alpha-amylase.
Authors: Jay Portnoy; Jeffrey D Miller; P Brock Williams; Ginger L Chew; J David Miller; Fares Zaitoun; Wanda Phipatanakul; Kevin Kennedy; Charles Barnes; Carl Grimes; Désirée Larenas-Linnemann; James Sublett; David Bernstein; Joann Blessing-Moore; David Khan; David Lang; Richard Nicklas; John Oppenheimer; Christopher Randolph; Diane Schuller; Sheldon Spector; Stephen A Tilles; Dana Wallace Journal: Ann Allergy Asthma Immunol Date: 2013-12 Impact factor: 6.347