Construction of pFUM003 expression vector with extracellular secretion properties

Probiotics are beneficial microorganisms that have been used in food production as well as health promotion over the centuries. Recombinant probiotics are used to express and transfer native or recombinant molecules to mucosal surface of digestive tract to promote efficiency in nutrition and health. Lactococcus lactis is a potential candidate for the production of useful biological proteins. Since there is not any vector nominated for this bacterium to show the extracellular protein secrition properties, therefore the aim of this study was to increase the efficiency of expression and secretion of recombinant proteins by adding transmission signal peptide usp45 to pBU003.
usp45 signal peptide has 81 nucleotides and previous studies indicated that it can also cause increase in the gene expression. In this study, after synthesising usp45 signal sequence, it was ligated into pBU003. Then the vector was transformed to Ecoli (MC1061). The recombinant plasmid named pFUM003 after “plasmid Ferdowsi University of Mashhad 003”.
Sequencing of recombinant plasmid containing usp45 showed that the plasmid had correct construction and the inserted sequence had exact match with the reference sequence (EU382094.1) reported in NCBI's GenBank.
The recombinant plasmid was named pFUM003. This recombinant plasmid structurally was correct and can be used to transmit into probiotics make them to benefit from extracellular protein production properties.