RNA interference (RNAi) is a posttranscriptional gene silencing method that is 
triggered by double-stranded RNA (dsRNA). RNAi is used to inactivate genes of 
interest and provides a genetic tool for loss-of-function studies in a variety 
of organisms.I have used this method to reveal the physiological roles of a 
number of endogenous proteins involved in mitochondrial DNA metabolism in 
Schneider cells, including the mitochondrial single-stranded DNA-binding 
protein. Here, I present experimental schemes of selective suppression of 
endogenous gene expression using RNAi in Drosophila Schneider S2 cells. With 
this method, the function of exogenous wild-type or mutant genes can be 
evaluated.