A. Kimberley McAllister, Nina Tang, Lawrence C. Katz, and Donald C.
Department of Neurobiology, Box 3209, Duke University Medical Center, Durham, NC 27710
The introduction of genetic material into cells and tissues of interest remains a rate-limiting step for molecular investigations in many fields, especially neurobiology. Many different methods have been developed to transfect cellsDNA-mediated gene transfer, microinjection, electroporation, lipofection, and viral transfectionand for many cell types, gene transfer using these methods has become a routine tool for studying gene regulation and function. However, many other cell types, particulary postmitotic neurons, have not been easily transfected by these methods.
In the late 1980s, John Sanford, Stephen Johnston, and colleagues developed a device that could potentially allow transfection of such resistant cells (Klein et al., 1987; Johnston, 1990). These inventors called this method biolistics, an anagram for biological ballistics that describes the process of shooting biological materials into living tissue. Biolistic transformation, which involves accelerating DNA-coated microprojectiles directly into cells, was originally designed to circumvent difficulties in transfecting plant cells. In the eight years since the method was first reported, Biolistic bombardment has also been proven effective in transfecting a wide variety of animal tissues as well as in both eukaryotic and prokaryotic microbes, mitochondria, and microbial and plant chloroplasts (Johnston, 1990; Klein et al., 1992; Pecorino and Lo, 1992; Jiao et al., 1993).
To study the signals which regulate neural