Scientists Coax Plants to Produce Proteins Useful in Vaccine Development

Scientists from the University of Pennsylvania School of Dental Medicine’s departments of Biochemistry and Pathology have utilized codon optimization to create a genetic engineering technique that persuades plants to produce foreign proteins suitable for use in vaccines. Published in Plant Physiology, the study, “Codon Optimization to Enhance Expression Yields Insights Into Chloroplast Translation,” focused on species-specific preferences by analyzing the genomes of 133 plant species to determine which codons were used most frequently to code for particular amino acids. The results helped researchers design software that converts DNA sequences into the sequence that would be preferred by the plants the team determined best suited for the task — lettuce and tobacco.

The findings revealed codon optimization — the process of exploiting an organism’s preference for which codon it uses to produce a given amino acid — has a significant impact on protein expression. The team was able to coax the plants to produce two specific proteins, one used in a hemophilia therapy, and another in a polio vaccine. This led to expression levels of hemophilia clotting factor five to six times higher than the native protein. It also created poliovirus protein levels approximately 26 times higher than the native sequence. By improving protein expression levels, the researchers say they are one step closer to bringing these therapies to clinical trials.