Application of Micromechanical Piercing Structures for Genetic Transformation of Nematodes

Several methods are available to accomplish gene transfer into mammalian cells, plant cells, yeast, and other organisms. Three of the most promising DNA delivery systems are electroporation (1 ,2 ), DNA-coated microprojectiles (3 ), and microinjection (4 ,5 ). Electroporation involves the formation of transient pores in biological membranes by the discharge of electrical current DNA diffuses into cells through the pores created by this process. The microprojectile gene transfer technique shoots particles coated with genetic materials into target cells. In the heavily studied free-having nematode Caenorhabditis elegans , the functional characterization of cloned genes has been greatly facilitated by the availability of an efficient DNA transformation system. The only procedure for transformation of C. elegans has been microinjection of DNA into the gonad of individual nematodes (4 ,5 ). Microinjection has also been used successfully for transforming the insect parasitic nematode Heterorhabditis bacteriophora (6 ). Although the available techniques have been successful in genetic transformation of various organisms, these techniques are expensive, laborious, and require considerable expertise.