Sequence diversity of the Bla g 4 cockroach allergen, homologous to lipocalins, from Blattella germanica

Kyoung Yong Jeong, Myung Hee Yi, Kyoung Jin Jeong, Haeseok Lee, Chein Soo Hong, Tai Soon Yong

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Background: The cockroach allergen Bla g 4, a putative lipocalin, is known to exhibit frequent sequence variations. However, the previously reported cDNA sequences are truncated at the N terminus. This study was undertaken to investigate the mechanisms by which these sequence variations are generated. Methods: Rapid amplification of cDNA ends PCR and RT-PCR were performed to obtain the full sequence of the Bla g 4 cDNA, and PCR was also used to clone the Bla g 4 genomic DNA. In addition, Bla g 4 protein variants were analyzed by two-dimensional gel electrophoresis. Results: Nine additional amino acid residues at the N terminus of Bla g 4 were identified, and 2 genes encoding Bla g 4, both of which consisted of 5 exons, were cloned. Examination of 34 clones of Bla g 4 cDNA obtained by RT-PCR revealed 14 variants. In particular, Bla g 4 sequences showed frequent clusters of variations in residues 38-45, 61-82 and 144-163. Differences in cDNA sequences may imply that RNA sequences are edited after transcription. More than 10 spots were identified between pH 5 and 7 upon two-dimensional gel electrophoresis, indicating that multiple variants of Bla g 4 are produced at the protein level. Conclusions: Genetic polymorphisms among individual cockroaches, the existence of multiple genes and sequence variations caused by RNA editing produce sequence diversity of Bla g 4, which may influence its allergenicity. The sequence information obtained in this study will be helpful for the standardization of the cockroach allergen and thereby aid in the development of diagnostics and immunotherapeutics.

Original languageEnglish
Pages (from-to)339-345
Number of pages7
JournalInternational Archives of Allergy and Immunology
Issue number4
Publication statusPublished - 2009 Mar

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


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