Genome-wide Approaches to Dissect Cellular Signaling by RNAi

An important aim upon completion of whole genome sequences is the functional analysis of all predicted gene products. Genetic approaches in the past have provided insights into requirement for gene products. New methods such as RNA interference (RNAi) allow silencing of specific genes on a genome-wide scale.

We have developed an approach to rapidly screen all genes encoded by the Drosophila genome using genome-wide RNAi library. Drosophila is one of the best-studied genetic model systems and has been instrumental to the identification of conserved pathway components with important roles from flies to humans. Treatment of cultured Drosophila cells with dsRNA leads to the efficient depletion of the corresponding transcript and the generation of specific and penetrant phenotypes. We have applied a high-throughput RNAi screen in macrophage-like cells to characterize the function of nearly all predicted Drosophila gene in cell growth and viability and several signaling pathways. Quantitative analysis showed that mutant phenotypes allowed classification of phenotypes into distinct functional classes.

The genome-wide RNAi library is adaptable for screening for many different cellular pathways and processes, which should ultimately facilitate the understanding of complex cellular networks. We will present results from genome-wide RNAi screens to comprehensively identify signaling pathway components and approaches to integrate data sets across different pathways.