WARF: P05264US

Peptide Extension for Enhancement of Transgene Expression in Chloroplasts


Thomas Ziegelhoffer, Sandra Austin-Phillips

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a method of modifying the chloroplast genome to enable increased expression of a desired protein.
OVERVIEWTransgenic plants are potential “chemical factories” for the production of industrially useful proteins, including pharmaceuticals. Conventionally, all parts of a transgenic plant contain the transgene. As an alternative, just the plant chloroplasts, the organelles responsible for photosynthesis, can be made transgenic. This offers several important advantages, including high levels of transgene expression and foreign protein accumulation. In addition, chloroplasts are not generally present in pollen, so genetically engineered chloroplasts are less likely to spread into unmodified native plants.
THE INVENTIONUW-Madison researchers have developed a method of modifying the chloroplast genome to enable increased expression of a desired protein. The method starts with a peptide extension consisting of two to 50 contiguous amino acids from the amino terminus of the well-expressed chloroplast protein PsbA. A nucleic acid sequence encoding the peptide extension is fused to a gene of interest. When this construct is inserted into the chloroplast genome, the peptide extension increases expression of the target protein.
  • Production of industrially useful proteins in transgenic plants
  • Results in a 50- to 100-fold increase in expression of the target gene
  • Provides a novel method of controlling gene expression in plasmids
  • May enhance production of cellulose-degrading enzymes, which are used in the conversion of cellulosic biomass to ethanol
  • May lead to an easier, less expensive and more environmentally friendly cellulose degradation process
Contact Information
For current licensing status, please contact Emily Bauer at or 608-960-9842.
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