Poster: Metabolic engineering
Abs #
293: Transgenic Expression of Human Granulocyte Colony-stimulating Factor in Rice
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Presenter: |
Ng, Wing-Man , nwm613@sinagirl.com |
Authors | Ng, Wing-Man (A) Sun, Samuel S. M. (A) | | Affiliations: |
(A): Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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Human granulocyte colony-stimulating factor (hG-CSF) is one of the hematopoietic growth factors. It stimulates the proliferation, differentiation and maturation of neutrophil granulocyte progenitor cells into mature neutrophils, which are the most important cellular defense mechanism against invading microorganisms. For the clinical application, hG-CSF provides an effective treatment for patients after receiving cytotoxic chemotherapy. Besides, its efficacy in surmounting neutropenia and mobilizing progenitor cells has been exploited in different disease areas.
Previous studies in our laboratory have been performed to express hG-CSF in Arabidopsis and tobacco plants. The expression level was about 0.2% of the total soluble seed protein. In this study, rice was used as bioreactor for production of recombinant hG-CSF (rhG-CSF). Several hG-CSF chimeric genes were constructed under the control of rice Glutelin-1 seed-specific promoter. In order to enhance the expression level of hG-CSF, three vacuolar sorting determinants were added to direct the rhG-CSF proteins to different parts of protein storage vacuole in rice endosperm, where the rhG-CSF proteins may be protected against degradation. Moreover, two constructs with hG-CSF fused with rice glutelin gene were made to enhance the expression level of rhG-CSF in rice.
Results from transgenic plants indicated that for the constructs with vacuolar sorting determinants, expression of rhG-CSF was found in the cell membrane fraction, suggesting the rhG-CSF protein was directed to the protein storage vacuole in rice. For hG-CSF fused with glutelin, expression of rhG-CSF was also detected by western blot. Sub-localization of the rhG-CSF protein in rice endosperm as well as its functional assay will be studied and presented.
