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Open data
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Basic information
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Title | cryo-EM structure of dimerized pre-B+5'ss complex | |||||||||
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![]() | spliceosome / splicing | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 24.0 Å | |||||||||
![]() | Zhang Z / Kumar V / Stark H / Luehrmann R | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural insights into the cross-exon to cross-intron spliceosome switch. Authors: Zhenwei Zhang / Vinay Kumar / Olexandr Dybkov / Cindy L Will / Jiayun Zhong / Sebastian E J Ludwig / Henning Urlaub / Berthold Kastner / Holger Stark / Reinhard Lührmann / ![]() ![]() Abstract: Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron. Alternatively, it can occur ...Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron. Alternatively, it can occur through an exon-defined pathway, whereby U2 binds the branch site located upstream of the defined exon and U1 snRNP interacts with the 5' splice site located directly downstream of it. The U4/U6.U5 tri-snRNP subsequently binds to produce a cross-intron (CI) or cross-exon (CE) pre-B complex, which is then converted to the spliceosomal B complex. Exon definition promotes the splicing of upstream introns and plays a key part in alternative splicing regulation. However, the three-dimensional structure of exon-defined spliceosomal complexes and the molecular mechanism of the conversion from a CE-organized to a CI-organized spliceosome, a pre-requisite for splicing catalysis, remain poorly understood. Here cryo-electron microscopy analyses of human CE pre-B complex and B-like complexes reveal extensive structural similarities with their CI counterparts. The results indicate that the CE and CI spliceosome assembly pathways converge already at the pre-B stage. Add-back experiments using purified CE pre-B complexes, coupled with cryo-electron microscopy, elucidate the order of the extensive remodelling events that accompany the formation of B complexes and B-like complexes. The molecular triggers and roles of B-specific proteins in these rearrangements are also identified. We show that CE pre-B complexes can productively bind in trans to a U1 snRNP-bound 5' splice site. Together, our studies provide new mechanistic insights into the CE to CI switch during spliceosome assembly and its effect on pre-mRNA splice site pairing at this stage. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 14.4 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 11.8 KB 11.8 KB | Display Display | ![]() |
Images | ![]() | 52.6 KB | ||
Filedesc metadata | ![]() | 3.7 KB | ||
Others | ![]() ![]() | 11.8 MB 11.8 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8qozC ![]() 8qp8C ![]() 8qp9C ![]() 8qpaC ![]() 8qpbC ![]() 8qpeC ![]() 8qpkC ![]() 8qxdC ![]() 8qzsC ![]() 8r08C ![]() 8r09C ![]() 8r0aC ![]() 8r0bC ![]() 8rm5C C: citing same article ( |
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Links
EMDB pages | ![]() ![]() |
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Map
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Voxel size | X=Y=Z: 4.64 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #1
File | emd_19868_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #2
File | emd_19868_half_map_2.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
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Sample components
-Entire : dimerized pre-B+5'ss complex
Entire | Name: dimerized pre-B+5'ss complex |
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Components |
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-Supramolecule #1: dimerized pre-B+5'ss complex
Supramolecule | Name: dimerized pre-B+5'ss complex / type: complex / ID: 1 / Parent: 0 |
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Source (natural) | Organism: ![]() |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 7.9 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: FEI FALCON III (4k x 4k) / Average electron dose: 60.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 3.5 µm / Nominal defocus min: 1.5 µm |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: OTHER / Details: ab initio |
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Final reconstruction | Resolution.type: BY AUTHOR / Resolution: 24.0 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 31671 |
Initial angle assignment | Type: MAXIMUM LIKELIHOOD |
Final angle assignment | Type: MAXIMUM LIKELIHOOD |