Localization of Prp8, Brr2, Snu114 and U4/U6 proteins in the yeast tri-snRNP by electron microscopy

@article{Hcker2008LocalizationOP,
  title={Localization of Prp8, Brr2, Snu114 and U4/U6 proteins in the yeast tri-snRNP by electron microscopy},
  author={Irina H{\"a}cker and Bjoern Sander and Monika M. Golas and Elmar Wolf and Elif Karag{\"o}z and Berthold Kastner and Holger Stark and Patrizia Fabrizio and Reinhard L{\"u}hrmann},
  journal={Nature Structural \&Molecular Biology},
  year={2008},
  volume={15},
  pages={1206-1212}
}
The U4/U6-U5 tri–small nuclear ribonucleoprotein (snRNP) is a major, evolutionarily highly conserved spliceosome subunit. Unwinding of its U4/U6 snRNA duplex is a central event of spliceosome activation that requires several components of the U5 portion of the tri-snRNP, including the RNA helicase Brr2, Prp8 and the GTPase Snu114. Here we report the EM projection structure of the Saccharomyces cerevisiae tri-snRNP. It shows a modular organization comprising three extruding domains that contact… 
The architecture of the spliceosomal U4/U6.U5 tri-snRNP
TLDR
Cryo-electron microscopy single-particle reconstruction of Saccharomyces cerevisiae tri-snRNP is used to reveal the essentially complete organization of its RNA and protein components, providing crucial insights into the activation process and the active site of the spliceosome.
Assembly and dynamics of the U4/U6 di-snRNP by single-molecule FRET
TLDR
This work has studied successive binding of all protein components to the snRNA duplex during di-snRNP assembly by electrophoretic mobility shift assay and accompanying conformational changes in the U4/U6 RNA 3-way junction by single-molecule FRET.
A protein map of the yeast activated spliceosome as obtained by electron microscopy.
TLDR
The spatial arrangement of proteins and snRNP subunits within the purified spliceosomal B(act) complex from Saccharomyces cerevisiae is elucidated using negative-stain immunoelectron microscopy, and structural insights into the remodeling events at thespliceosome during its transformation from the B to the B( act) complex are provided.
Protein localisation by electron microscopy reveals the architecture of the yeast spliceosomal B complex
TLDR
The B complex exhibited a triangular shape with main body, head and neck domains and was assigned to the respective snRNPs, providing the first detailed picture of the subunit architecture and protein arrangements of the B complex.
The 3.8 Å structure of the U4/U6.U5 tri-snRNP: Insights into spliceosome assembly and catalysis
TLDR
The three-dimensional structure of a Saccharomyces cerevisiae U4/U6 subcomplex, which comprises the U5 small nuclear ribonucleoprotein (snRNP), the U4 and U6 small nuclear RNA (snRNA) duplex, and a number of protein factors, is determined and reveals the molecular choreography of the snRNAs in the activation process of the spliceosomal ribozyme.
Sad1 Counteracts Brr2-Mediated Dissociation of U4/U6.U5 in Tri-snRNP Homeostasis
TLDR
It is shown here that Sad1 plays a role in maintaining a functional form of the tri- SnRNP by promoting the association of U5 snRNP with U4/U6 di-snRNP, and counteracting Brr2-mediated dissociation of tri-SnRNP.
The N-terminus of Prp1 (Prp6/U5-102 K) is essential for spliceosome activation in vivo
TLDR
It is demonstrated that structural integrity of the N-terminus is required to mediate a splicing event, but is not necessary for the assembly of spliceosomes.
Structural evidence for consecutive Hel308-like modules in the spliceosomal ATPase Brr2
TLDR
The structural model and mutagenesis data suggest that Brr2 shares a similar helicase mechanism with Hel308, and it is found that Hel308-II interacts with Prp8 and Snu114 in vitro and in vivo and facilitates the binding of the Brr 2–Prp8-CTR complex to U4/U6.
Common design principles in the spliceosomal RNA helicase Brr2 and in the Hel308 DNA helicase.
TLDR
A structural model of the N-terminal active cassette of Brr2 is devised, highlighting how the RecA-like domains and the Sec63 unit form a functional entity that appears suitable for unidirectional and processive RNA duplex unwinding during spliceosome activation and disassembly.
Brr2p carboxy-terminal Sec63 domain modulates Prp16 splicing RNA helicase
TLDR
It is proposed that the carboxy-terminal helicase module of Brr2p acquired a regulatory function that allows Brr 2p to modulate the ATPase activity of Prp16p in the spliceosome by controlling access to its RNA substrate/cofactor.
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TLDR
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TLDR
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