A more complete understanding of the biology of adult stem cells could yield important insights toward devising effective cell-based regenerative therapies to treat disease. The germline stem cells (GSCs) in the fruit flyDrosophila melanogasterare an excellent in vivo model for the study of adult stem cell biology. There is increasing evidence from a growing field that microRNAs (miRNAs) play important roles in controlling many aspects of stem-cell biology. Using straightforward genetic manipulations combined with well-established cell biological analysis techniques, we and others have found that the miRNA pathway regulates the cell division rate ofDrosophilaGSCs as well as the maintenance of the GSCs in their niche. In this chapter, we offer a detailed, self-contained description of a general method to assess the in vivo functions of miRNAs in the GSCs of theDrosophilaovary.
