In this completely updated and expanded edition of a classic bench manual, hands-on experts take advantage of the latest advances in ribozyme, DNAzyme, hammerhead ribozymes and derivatives, and RNA interference technologies to describe in detail the exciting and successful methods now available for gene inactivation in vitro and in vivo. Their optimized techniques employ hairpin ribozymes, DNAzymes, hammerhead ribozymes and derivatives, group I intron ribozymes, RNase P ribozymes, and siRNAs, as well as general methods for RNA structure analysis, delivery of oligonucleotides, and gene therapy. Also provided are novel methods for identifying accessible cellular mRNA sites; group I intron and RNAse P ribozyme protocols for effective design, selection, and therapeutic applications; and the latest RNAi methods for sequence-specific gene silencing in a wide variety of organisms. Additional techniques cover the analysis of ribozyme structures and conformational transitions using nucleotide analog interference mapping and fluorescence resonance energy transfer, the use of ribozymes in clinical and gene therapy, and the use of ribozymes and DNAzymes in rodent models of human disease. Each proven protocol includes a background introduction outlining the principle behind the technique, step-by-step instructions, lists of equipment and reagents, and tips on troubleshooting and avoiding known pitfalls. Comprehensive and up-to-date, Ribozymes and siRNA Protocols details for experienced and novice investigators alike the many exciting advances in our understanding of nucleic acid enzymes, as well as demonstrating how they may be used to analyze gene function and target validation, and to productively develop novel therapeutics for human diseases.