Using Structural Biology to Characterize the Schizosaccharomyces pombe Spliceosome

Abstract

The spliceosome is a dynamic macromolecular machine composed of five different small nuclear ribonucleoproteins (snRNPs), the Nineteen Complex (NTC), RNA helicases, and other proteins that catalyze the removal of introns from pre-mRNA. Although the spliceosome has been extensively studied, there are still many unanswered questions regarding the molecular mechanisms of pre-mRNA splicing. In this work we used the Schizosaccharomyces pombe model system to characterize the structure and function of the spliceosome. By examining the in vitro RNA ability of S. pombe Cdc5, a core component of the NTC, we were able to propose a mechanism where protein components of the NTC can bind and stabilize RNA within the active site of the spliceosome. We also used an RNA helicase mutant, S. pombe prp16-1, to isolate a second step splicing complex. This work has provided insight into the general mechanisms on how the spliceosome functions to process pre-mRNA.