William Heiser, Ph.D., Research and Development Department, Genetic Systems Division, Bio-Rad Laboratories, 2000 Alfred Nobel Drive, Hercules, CA 94547
We have found that the most important factors which must be optimized in Biolistic transformation are target distance and microparticle size. Changing most other parameters, within a broad range, usually has minimal effect on transformation efficiencies. In this report we describe a strategy for optimizing Biolistic transformation. We use two model systems to show how this strategy can be employed by developing optimal conditions for stable transformation of yeast and transient expression in cauliflower stem sections.
The Biolistic process, first reported by Sanford, et al. (1987), is a method by which foreign substances are introduced into intact cells and tissues via high-velocity microprojectiles. Transformation of biological material using the Biolistic method has been shown to be a valuable technique for delivering DNA into the cells of plant (Klein, et al., 1988 a, b), animal (Williams, et al., 1991), and microbial species (Shark, et al., 1991), as well as into subcellular organelles (Johnston, et al., 1988; Daniell, et al., 1991). Achieving high rates of DNA expression in each of these cases often requires that time be spent in optimizing some of the parameters involved in transformation. However, this task can be difficult, considering the large number of parameters which can be varied in the system. In addition, there has been a recent modification of the commercially available instrument which now uses a helium-powered acceleration system (Sanford, et al., 1991). This report outlines an approach to optimizing