Receptor-mediated endocytosis as a selection force to enrich bacteria expressing rhodostomin on their surface

Previously, we developed a TraT display system to express snake venom rhodo stomin (RHO), a disintegrin, on the external surface of Escherichia coli [J Biomed Sci 6:64-70;1999], To show a new potential use of the TraT display system, we employed a biotin labeling technique coupled with SDS-PAGE and f low cytometry analyses to further demonstrate and confirm the expression of TraT-RHO on the E,coli surface. We also showed that the expression of TraT -RHO on the cell surface not only facilitated the bacteria adhesion to BHK- 21 cells but also induced bacterial internalization into BHK-21 cells. This feature allowed us to enrich the TraT-RHO expression bacteria about 10,000 -fold starting with a mixture of TraT-RHO bacteria with beta-galactosidase- positive babe; ria in a ratio of 10(2):10(7) through four cycles of BHK-21 cell endocytosis and replating of engulfed bacteria on agar plates, We ther efore suggest that the TraT display system can be applied to select out bac teria expressing a specific peptide sequence from a large population of dis play library through the process of receptor-mediated endocytosis and reamp lification cycles. Copyright (C) 2000 National Science Council, ROC and S. Karger AG, Basel.