|
1
|
Beusch I, Rao B, Studer MK, Luhovska T, Šukytė V, Lei S, Oses-Prieto J, SeGraves E, Burlingame A, Jonas S, Madhani HD. Targeted high-throughput mutagenesis of the human spliceosome reveals its in vivo operating principles. Mol Cell 2023; 83:2578-2594.e9. [PMID: 37402368 PMCID: PMC10484158 DOI: 10.1016/j.molcel.2023.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 03/15/2023] [Accepted: 06/02/2023] [Indexed: 07/06/2023]
Abstract
The spliceosome is a staggeringly complex machine, comprising, in humans, 5 snRNAs and >150 proteins. We scaled haploid CRISPR-Cas9 base editing to target the entire human spliceosome and investigated the mutants using the U2 snRNP/SF3b inhibitor, pladienolide B. Hypersensitive substitutions define functional sites in the U1/U2-containing A complex but also in components that act as late as the second chemical step after SF3b is dissociated. Viable resistance substitutions map not only to the pladienolide B-binding site but also to the G-patch domain of SUGP1, which lacks orthologs in yeast. We used these mutants and biochemical approaches to identify the spliceosomal disassemblase DHX15/hPrp43 as the ATPase ligand for SUGP1. These and other data support a model in which SUGP1 promotes splicing fidelity by triggering early spliceosome disassembly in response to kinetic blocks. Our approach provides a template for the analysis of essential cellular machines in humans.
Collapse
Affiliation(s)
- Irene Beusch
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Beiduo Rao
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Michael K Studer
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Tetiana Luhovska
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Viktorija Šukytė
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Susan Lei
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, USA
| | - Em SeGraves
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, USA
| | - Stefanie Jonas
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Hiten D Madhani
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA.
| |
Collapse
|