Transcript stabilization by mRNA sequences from hrpA of Pseudomonas syringae

Production of heterologous proteins in bacteria is one of the main applications of biotechnology. Although several high-efficiency expression systems have been developed, different steps in protein production may become rate-limiting depending on the production system and the protein being produced. One bottle neck can be the instability of the mRNA. We have used fragments of the unusually long-living mRNA hrpA from the plant pathogenic bacteria Pseudomonas syringae pathovars tomato and phaseolicola to increase the half-lives of heterologous transcripts. The stabilizing effect was extended to Escherichia coli, as half-lives of several heterologous transcripts were increased from a few minutes to up to 19 min. Production of heterologous proteins was also increased manifold by the addition of the stabilizing hrpA elements. We have mapped the regions of the hrpA transcript necessary and sufficient for the stabilization process.