Transgenic Research

, Volume 12, Issue 6, pp 683–691 | Cite as

Expression of the B Subunit of E. coli Heat-labile Enterotoxin in the Chloroplasts of Plants and its Characterization

  • Tae-Jin Kang
  • Nguyen-Hoang Loc
  • Mi-Ok Jang
  • Yong-Suk Jang
  • Young-Sook Kim
  • Jo-Eun Seo
  • Moon-Sik Yang


Transgenic chloroplasts have become attractive systems for heterologous gene expressions because of unique advantages. Here, we report a feasibility study for producing the nontoxic B subunit of Escherichia coli heat-labile enterotoxin (LTB) via chloroplast transformation of tobacco. Stable site-specific integration of the LTB gene into chloroplast genome was confirmed by PCR and genomic Southern blot analysis in transformed plants. Immunoblot analysis indicated that plant-derived LTB protein was oligomeric, and dissociated after boiling. Pentameric LTB molecules were the dominant molecular species in LTB isolated from transgenic tobacco leaf tissues. The amount of LTB protein detected in transplastomic tobacco leaf was approximately 2.5% of the total soluble plant protein, approximately 250-fold higher than in plants generated via nuclear transformation. The GM1–ELISA binding assay indicated that chloroplast-synthesized LTB protein bound to GM1-ganglioside receptors. LTB protein with biochemical properties identical to native LTB protein in the chloroplast of edible plants opens the way for inexpensive, safe, and effective plant-based edible vaccines for humans and animals.

B subunit of E. coli heat-labile enterotoxin (LTB) chloroplast transformation edible vaccine homologous recombination homoplastomy 


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Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • Tae-Jin Kang
    • 1
  • Nguyen-Hoang Loc
    • 2
  • Mi-Ok Jang
    • 2
  • Yong-Suk Jang
    • 2
  • Young-Sook Kim
    • 3
  • Jo-Eun Seo
    • 4
  • Moon-Sik Yang
    • 2
  1. 1.Basic Sciences Research Institute, Chonbuk National UniversityJeonjuSouth Korea
  2. 2.Division of Biological Sciences and the Research Center for Bioactive MaterialsChonbuk National UniversityJeonjuSouth Korea
  3. 3.Institute of Molecular Biology and Genetics, Chonbuk National UniversityJeonjuSouth Korea
  4. 4.Department of Molecular and Genomic MedicineCollege of Medicine, Seoul National UniversitySeoul

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