New perspectives into bacterial DNA transfer to human cells.

The type IV secretion system (T4SS) VirB/D4 of the facultative intracellular pathogen Bartonella henselae is known to translocate bacterial effector proteins into human cells. Two recent reports on DNA transfer into human cells have demonstrated the versatility of this bacterial secretion system for macromolecular substrate transfer. Moreover, these findings have opened the possibility for developing new tools for DNA delivery into specific human cell types. DNA can be introduced into these cells covalently attached to a site-specific integrase with potential target sequences in the human genome. This novel DNA delivery system is discussed in the context of existing methods for genetic modification of human cells.