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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 158232, 16 pages
http://dx.doi.org/10.1155/2012/158232
Review Article

Stable Plastid Transformation for High-Level Recombinant Protein Expression: Promises and Challenges

1Department of Biological Science and Engineering, Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
2School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710032, China
3State Key Laboratory of Cancer Biology, Department of Biopharmaceutics School of Pharmacy, Fourth Military Medical University, Xi’an, Shaanxi 710032, China
4Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
5Institute of Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China

Received 17 May 2012; Revised 10 August 2012; Accepted 24 August 2012

Academic Editor: Elvira Gonzalez De Mejia

Copyright © 2012 Meili Gao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Plants are a promising expression system for the production of recombinant proteins. However, low protein productivity remains a major obstacle that limits extensive commercialization of whole plant and plant cell bioproduction platform. Plastid genetic engineering offers several advantages, including high levels of transgenic expression, transgenic containment via maternal inheritance, and multigene expression in a single transformation event. In recent years, the development of optimized expression strategies has given a huge boost to the exploitation of plastids in molecular farming. The driving forces behind the high expression level of plastid bioreactors include codon optimization, promoters and UTRs, genotypic modifications, endogenous enhancer and regulatory elements, posttranslational modification, and proteolysis. Exciting progress of the high expression level has been made with the plastid-based production of two particularly important classes of pharmaceuticals: vaccine antigens, therapeutic proteins, and antibiotics and enzymes. Approaches to overcome and solve the associated challenges of this culture system that include low transformation frequencies, the formation of inclusion bodies, and purification of recombinant proteins will also be discussed.