Strategies for the Design of Random siRNA Libraries and the Selection of anti-GFP siRNAs

Various methods have been devised to elucidate gene function in a highthroughput format. With the potential to silence any gene once the sequence is known, small, interfering RNAs (siRNAs) have been considered ideal for functional analysis and gene target validation (1 –3 ). Furthermore, the technology has unprecedented target flexibility. By performing RNAi on a large scale using siRNA libraries, this reverse-genetic method can essentially be used as a forward-genetic screening tool. In this respect, genomewide siRNA screens in Caenorhabditis elegans using libraries of in vitro-transcribed long doublestranded RNAs (dsRNAs) have been useful in gene discovery and functional annotation in various processes, including embryonic development (4 ,5 ).