Abstract
Pre-mRNA splicing is a critical step in eukaryotic gene expression, which involves removal of noncoding intron sequences from pre-mRNA and ligation of the remaining exon sequences to make a mature message. Splicing is carried out by a large ribonucleoprotein complex called the spliceosome. Since the first description of the pre-mRNA splicing reaction in the 1970s, elegant genetic and biochemical studies have revealed that the enzyme that catalyzes the reaction, the spliceosome, is an exquisitely dynamic macromolecular machine, and its RNA and protein components undergo highly ordered, tightly coordinated rearrangements in order to carry out intron recognition and splicing catalysis. Studies using the genetically tractable unicellular eukaryote budding yeast (Saccharomyces cerevisiae) have played an instrumental role in deciphering splicing mechanisms. In this chapter, we discuss how yeast genetics has been used to deepen our understanding of the mechanism of splicing and explore the potential for future mechanistic insights using S. cerevisiae as an experimental tool.