Gene Transfer Using Targeted Filamentous Bacteriophage

Abstract

Phage-mediated gene transfer offers an alternative method of introducing genes into specific cell types, including cell lines (1–4) and primary cell cultures (see Fig. 1). Recent studies demonstrate that filamentous bacteriophages can be engineered to transfer genes to mammalian cells by attaching a targeting ligand to the phage surface either noncovalently (1) or genetically (2–4) and, thus, directing phage particles to specific cell surface receptors (see Fig. 1). Successful gene transfer and subsequent protein expression is measured using a reporter gene such as green fluorescent protein (GFP), neomycin phosphotransferase, or β-galactosidase. In fact, any gene with an appropriate mammalian transcriptional promoter and polyadenylation signal can be incorporated into a ligand-targeted phage vector (see Note 1). It is this combination of ligand retargeting and insertion of a mammalian expression cassette that confers mammalian tropism to bacteriophage. These modified phage act like nonproductive animal viral vectors but can be propagated and manipulated genetically with all the conveniences of a phage vector.