Schematic representation of pNZ8148-SPUsp45-MpEGF vector expression of MpEGF in L. lactis . A 159-bp DNA fragment encoding mature porcine EGF (MpEGF) was fused in frame with an 81-bp DNA fragment containing the Usp45 signal peptide, derived from the predominant L. lactis-secreted protein. In this plasmid, pEGF expression is controlled by the nisin-inducible promoter (P
). The pNZ8148-SPUsp45-MpEGF carries the chloramphenicol resistance marker (cm).