Blood proteins probably make you think of animals, not
plants, but plant science has found a way to produce human serum albumin (HSA)
in rice. A team lead by ASPB member Daichang Yang at Wuhan University in China
has published their advance in the Proceedings of the
National Academy of Sciences this week; the paper was also featured in a
news article in The
HSA is used in treating severe blood loss, burn injuries,
and liver disease among other conditions as well as in commercial applications
as an additive to cell culture media, a carrier for active compounds in
medications, and in vaccine production. HSA is typically isolated from human
plasma, the liquid portion of blood, where it is the most abundant protein. However,
blood donors can be in short supply and there exists a theoretical risk of
contracting bloodborne infectious diseases such as HIV/AIDS and hepatitis—a
risk that can be eliminated by production of the protein in plants. Researchers
are also able to circumvent several issues surrounding typical recombinant
protein production schemes from microbial contamination to yield using rice to
produce HSA in an economical manner. As the global demand for HSA exceeds 500
tons per year, an additional source of the pure protein would be welcomed.
Yang He and colleagues utilized a natural protein storage
organ, the endosperm located within the rice grain, where they obtained
approximately 10% of total soluble protein as HSA. Important for the future
commercialization of rice HSA, the structure, function, and immunogenicity of
the rice-produced protein are equivalent to plasma isolated HSA. While
everything is on track for commercialization of rice HSA, several regulatory
hurdles, from growing genetically engineered plants to clinical trials, must be
In the meantime, kudos to He and colleagues for blurring
the boundaries between plant science and biomedical research.
Citation: Yang He,
Tingting Ning, Tingting Xie, Qingchuan Qiu, Liping Zhang, Yunfang Sun, Daiming
Jiang, Kai Fu, Fei Yin, Wenjing Zhang, Lang Shen, Hui Wang, Jianjun Li, Qishan
Lin, Yunxia Sun, Hongzhen Li, Yingguo Zho, and Diachang Yang. (2011).
production of functional human serum albumin from transgenic rice seeds. Proceedings
of the National Academy of Sciences, 10.1073/pnas.1109736108.
Protein from Rice.” The Scientist, October 31, 2011.