Drosophilacell lines are valuable tools to study a number of cellular processes, including DNA damage responses and cell cycle checkpoint control. Using an in vitro system instead of a whole organism has two main advantages: it saves time and simple and effective molecular techniques are available. It has been shown thatDrosophilacells, similarly to mammalian cells, display cell cycle checkpoint pathways required to survive DNA damaging events (de Vries et al. 2005,Journal of Cell Science118, 1833–1842; Bae et al. 1995,Experimental Cell Research217, 541–545). Moreover, a number of proteins involved in checkpoint and cell cycle control in mammals are highly conserved among different species, includingDrosophila(de Vries et al. 2005,Journal of Cell Science118, 1833–1842; Bae et al. 1995,Experimental Cell Research217, 541–545; LaRocque et al. 2007,Genetics175, 1023–1033; Sibon et al. 1999,Current Biology9, 302–312; Purdy et al. 2005,Journal of Cell Science118, 3305–3315). Because of straightforward and highly efficient methods to downregulate specific transcripts inDrosophilacells, these cells are an excellent system for genome-wide RNA interference (RNAi) screens. Thus, the following methods, assays and techniques: Drosophila cell culture, RNAi, introducing DNA damaging events, determination of cell cycle arrest, and determination of cell cycle distributions described here may well be applied to identifying new players in checkpoint mechanisms and will be helpful to investigate the function of these new players in detail. Results obtained with studies using in vitro systems can subsequently be extended to studies in the complete organism as described in the chapters provided by the Su laboratory and the Takada laboratory.
