Abstract: The present invention provides bacterial vectors and fusion proteins containing a TTSS polypeptide, compositions of such fusion proteins including polynucleotides, and methods of delivering one or more genes into a target cell that involve contacting the cell with a composition that includes such a fusion protein. Compositions and methods of gene delivery that involve a bacterium and a TAT, Antp, or HSV VP22 polypeptide are also disclosed. The invention also concerns methods of delivering one or more genes into a target cell utilizing a bacterium capable of becoming internalized within the cell, wherein the bacterium includes one or more genes targeted for delivery to the cell, a gene encoding an RNA polymerase, and a gene that causes lysis of the bacterium.