Minor tri-snRNP · Structural basis of human U4atac/U6atac•U5 tri-snRNP assembly

Minor spliceosome is responsible for the removal of a rare class of introns that are present in many essential genes. Despite its fundamental importance, much information remains elusive for a comprehensive understanding of minor spliceosome assembly and the molecular basis of the diseases associated with its malfunctions in human. In this proposal, I will investigate the assembly process of U4atac/U6atac•U5 tri-snRNP (minor tri-snRNP) by isolating relevant complexes from human cells and determining their structures using cryo-electron microscopy (cryo-EM). The U4atac/U6atac•U5 tri-snRNP is the largest pre-assembled building block of the minor spliceosome. By applying cryo-EM and proteomics, we will reveal the spatial organization and composition of the minor tri-snRNP, while the structures of its assembly intermediates will shed light on the role of assembly chaperones in the tri-snRNP maturation. Consequently, these findings will provide clues as to how minor spliceosome assembles to achieve its complex function.Recent advances in the field of cryo-EM have opened up the possibility to study large and dynamic spliceosomal complexes at a molecular level. With our lab’s expertise in pre-mRNA splicing, cryo-EM and mammalian cell culture, we are perfectly positioned to exploit these new technologies to gain mechanistic insights into the assembly of the minor spliceosome.