Conversion of Bacteria l Gene Products to Secretion-Competent Fusion Protein s

We describe an efficient and easy proc e dure that allows the generation, detection and secretion of foreign proteins by the s e cretion apparatus of E. coli hemolysin. Th e gene (or gene fragment) encoding the fo r eign protein (or protein domain) is inserted in-frame into a residual portion of the h e molysin gene (hlyA ), encoding the HlyA s e cretion signal (HlyA s ). Generally, the e x pressed fusion is efficiently secreted into th e culture supernatant of the producing strain . The new approach allows the direct genera tion of fusion proteins from genomic DNA fragments. The successful use of this meth od is demonstrated by cloning of random chromosomal DNA fragments from Salmo nella typhimurium .