Gene Transfer by Electroporation in Tetrahymena

Tetrahymena thermophila is a free-living ciliated protozoan useful in cell biological and molecular genetic studies. Recently DNA-mediated transformation has been developed for this microorganism (1 ), and used to study the mechanisms of genome rearrangement (2 –4 ) and structure-function relationships of the RNA component of telomerase, an enzyme responsible for synthesis of chromosomal ends (5 ,6 ). Tetrahymena is also an interesting eukaryotic model for studying cell biological processes, such as cell motility, exocytosis, and pattern formation. Furthermore, recent evidence showed that Tetrahymena is one of only a few eukaryotic organisms known in which DNA recombination activity of transforming DNA is known to be exclusively homologous (7 –10 ). Thus, gene replacement can be used in Tetrahymena as a tool to address fundamental problems in molecular cell biology.