Lactococcus is an attractive option for use as a recombinant bacterial vector due to its GRAS status. Apart from being non-pathogenic and non invasive, they have the capacity to secrete proteins on the cell surface or extracellularly. In addition, the size of the bacteria is similar to biodegradable micro particles, which are known to be taken up by the specialized M cells in the Payer's patches of the gastrointestinal tract and the migratory pathways of the mucosal lymphocytes. These features render the bacterium to be the ideal choice for the safe production of commercially significant foreign proteins.
This project would concentrate on several very important aspects. Due to the unavailability of ready-to-use cloning and expression vectors for Gram positive organisms, the initial part of the project would be to develop the plasmids which had been isolated and constructed from the previous Top Down project into useful cloning and expression vectors. Changing the promoters and cloning new genes to give specialized functions to the recombinant proteins will hopefully achieve this. Promoter activity will be confirmed by using reporter genes. Specific markers will also be included to make the detection of recombinants easier.
EXECUTIVE SUMMARY
Project Title:
Development of Recombinant Bacteria fro Delivery of
Functional Proteins
Secondly, the present and newly developed vectors will be used to clone genes coding for useful proteins. The wide range of genes proposed to be cloned in this projects will give us the added advantage of seeking the optimum conditions for gene expression in Lactococcus. These proteins are specifically identified due to their importance in various industries such as food, medical, livestock and aquaculture. The bacterial host to be used will also be developed to maximize the expression of foreign proteins. This will be carried out for example by site directed deletion of genes coding for proteases, which are enzymes known for degrading proteins.
Finally, genome wide expression studies of the transformed strains as well as immunogenic studies will be carried out utilizing available systems.
Period of the project : 3 Years (2003 - 2005)
Project Status- On-going