EMD-47164

Single-particle
3.57 Å
EMD-47164 Deposition: 01/10/2024
Map released: 25/12/2024
Last modified: 01/01/2025
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-47164

Yeast post-catalytic P complex spliceosome, focussed refinement on the Cwc22 N-terminal domain

EMD-47164

Single-particle
3.57 Å
EMD-47164 Deposition: 01/10/2024
Map released: 25/12/2024
Last modified: 01/01/2025
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Saccharomyces cerevisiae
Sample: Yeast post-catalytic P complex spliceosome

Deposition Authors: Wilkinson ME , Hoskins AA
Control of 3' splice site selection by the yeast splicing factor Fyv6.
PUBMED: 39688371
DOI: doi:10.7554/eLife.100449
ISSN: 2050-084X
Abstract:
Pre-mRNA splicing is catalyzed in two steps: 5' splice site (SS) cleavage and exon ligation. A number of proteins transiently associate with spliceosomes to specifically impact these steps (first and second step factors). We recently identified Fyv6 (FAM192A in humans) as a second step factor in Saccharomyces cerevisiae; however, we did not determine how widespread Fyv6's impact is on the transcriptome. To answer this question, we have used RNA sequencing (RNA-seq) to analyze changes in splicing. These results show that loss of Fyv6 results in activation of non-consensus, branch point (BP) proximal 3' SS transcriptome-wide. To identify the molecular basis of these observations, we determined a high-resolution cryo-electron microscopy (cryo-EM) structure of a yeast product complex spliceosome containing Fyv6 at 2.3 Å. The structure reveals that Fyv6 is the only second step factor that contacts the Prp22 ATPase and that Fyv6 binding is mutually exclusive with that of the first step factor Yju2. We then use this structure to dissect Fyv6 functional domains and interpret results of a genetic screen for fyv6Δ suppressor mutations. The combined transcriptomic, structural, and genetic studies allow us to propose a model in which Yju2/Fyv6 exchange facilitates exon ligation and Fyv6 promotes usage of consensus, BP distal 3' SS.