Structural Basis of Brr2-Prp8 Interactions and Implications for U5 snRNP Biogenesis and the Spliceosome Active Site
| Autor: | Andrew J. Newman, Thi Hoang Duong Nguyen, Kiyoshi Nagai, Hiroyuki Oshikane, Wojciech P. Galej, Jade Li |
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| Rok vydání: | 2013 |
| Předmět: |
Genetics
Spliceosome Saccharomyces cerevisiae Proteins Protein Conformation Small Nuclear Ribonucleoprotein Particle RNA-Binding Proteins RNA RNA-binding protein Prp24 Biology Article Cell biology Structural Biology Catalytic Domain RNA Small Nuclear Mutation Spliceosomes snRNP Molecular Biology RNA Helicases Small nuclear RNA Protein Binding SnRNP Biogenesis |
| Zdroj: | Structure(London, England:1993) |
| ISSN: | 0969-2126 |
| DOI: | 10.1016/j.str.2013.04.017 |
| Popis: | Summary The U5 small nuclear ribonucleoprotein particle (snRNP) helicase Brr2 disrupts the U4/U6 small nuclear RNA (snRNA) duplex and allows U6 snRNA to engage in an intricate RNA network at the active center of the spliceosome. Here, we present the structure of yeast Brr2 in complex with the Jab1/MPN domain of Prp8, which stimulates Brr2 activity. Contrary to previous reports, our crystal structure and mutagenesis data show that the Jab1/MPN domain binds exclusively to the N-terminal helicase cassette. The residues in the Jab1/MPN domain, whose mutations in human Prp8 cause the degenerative eye disease retinitis pigmentosa, are found at or near the interface with Brr2, clarifying its molecular pathology. In the cytoplasm, Prp8 forms a precursor complex with U5 snRNA, seven Sm proteins, Snu114, and Aar2, but after nuclear import, Brr2 replaces Aar2 to form mature U5 snRNP. Our structure explains why Aar2 and Brr2 are mutually exclusive and provides important insights into the assembly of U5 snRNP. Graphical Abstract Highlights • We report the structure of Brr2 helicase in complex with the Jab1/MPN domain of Prp8 • Retinitis pigmentosa mutations in the Jab1/MPN domain of Prp8 disrupt this complex • Mechanism is proposed for the U4/U6 snRNA duplex unwinding and spliceosome activation • The Brr2-Jab1/MPN and Aar2-Prp8 complexes provide insight into U5 snRNP biogenesis Brr2 helicase unwinds the U4/U6 snRNA duplex and introduces U6 snRNA into the active site cavity of the spliceosome formed within Prp8. Nguyen et al. report a crystal structure of Brr2 helicase together with the Jab1/MPN domain of Prp8 and provide new insights into this process as well as retinitis pigmentosa. |
| Databáze: | OpenAIRE |
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