Poster: Late and Moved Abstracts

Abs # 980: Improvement of human lysozyme expression in transgenic rice grain by employing the puroindoline b promoter and signal peptide of wheat (Triticum aesvestium)

Presenter:	Yang, Daichang
Authors	Yang, Daichang  (A)   Hennegan, Kevin  (A)   Nguyen, Diane  (A)   Wu, Liying  (A)   Huang, Jianmin  (A)   Guo, Fengli  (B)   Lu, Stephen  (A)   Watkins, C. Simon  (B)   Huang, Ning  (A)
Affiliations:	(A): Ventria Bioscience (B): Department of Cell Biology and Physiology, University of Pittsburgh, PA 15261, USA
Web Site:	http://www.ventriabio.com

Heterologous protein expression levels in transgenic plants are of critical importance in the production of plant-made pharmaceuticals (PMPs). We studied a puroindoline b promoter and signal peptide (Tapur) driving human lysozyme expression in rice endosperm. The results demonstrated that human lysozyme expressed under the control of the Tapur cassette is seed-specific, readily extractable, active, and properly processed. The results from immuno-electron microscopy indicated that lysozyme expressed from this cassette is localized in protein bodies I and II in rice endosperm cells. In wheat grain, puroindoline b protein is associated with the starch granule, and lysozyme expressed in rice under the control of the glutelin-1 (Gt1) cassette is stored in protein body II. We successfully employed a strategy improving the expression of human lysozyme in transgenic rice grain by combining the Tapur cassette with our well established Gt1 expression system. The results demonstrated that when the two expression cassettes were combined, the expression level of human lysozyme increased from 0.52 % to 0.92 % grain weight in the best line, indicating an additive effect on expression of human lysozyme in rice grain.