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          Institute: MPI für Biochemie     Collection: Structural Biology (W. Baumeister)     Display Documents

ID: 41768.0, MPI für Biochemie / Structural Biology (W. Baumeister)
Cryoelectron microscopy and cryoelectron tomography of the nuclear pre-mRNA processing machine
Authors:Medalia, O.; Typke, D.; Hegerl, R.; Angenitzki, M.; Sperling, J.; Sperling, R.
Date of Publication (YYYY-MM-DD):2002-04
Title of Journal:Journal of Structural Biology
Journal Abbrev.:J. Struct. Biol.
Issue / Number:1-2
Start Page:74
End Page:84
Review Status:Peer-review
Audience:Not Specified
Abstract / Description:Large nuclear ribonucleoprotein particles, which can be viewed as the naturally assembled precursor messenger RNA (pre-mRNA) processing machine, were analyzed in frozen-hydrated preparations by cryoelectron microscopy. A general and reproducible strategy for preparing ice-embedded large nuclear ribonucleoprotein (lnRNP) particles at sufficiently high concentration was developed. Taking advantage of their negatively charged components, the lnRNP particles are adsorbed and thus concentrated on a positively charged lipid monolayer while preserving their native structure. Using this approach we carried out cryoelectron tomography and three-dimensional image reconstruction of individual InRNP particles. The study revealed a structure similar to that of negatively stained particles studied previously, yet with additional features. The small additional domain visualized in negative stain appeared to be larger in the ice preparations. In addition, using image restoration from focus series of ice-embedded InRNP particles, new features such as holes within the subunits were visualized in two dimensions, and it was shown that the subunits are interconnected via a fiber, very likely formed by the pre-mRNA. This finding supports the model that each subunit represents a spliceosome that splices out the intron wound around it. (C) 2002 Elsevier Science (USA). All rights reserved.
Free Keywords:InRNP complexes; cryoelectron microscopy; charged lipid monolayer; cryoelectron tomography; image restoration; three- dimensional image reconstruction; pre-mRNA processing
Comment of the Author/Creator:Date: 2002, APR-MAY
External Publication Status:published
Document Type:Article
Communicated by:Anton Hillebrand
Affiliations:MPI für Biochemie/Molecular Structural Biology (W. Baumeister)/Research Group Hegerl
External Affiliations:Hebrew Univ Jerusalem, Dept Genet, IL-91904 Jerusalem, Israel; Hebrew Univ Jerusalem, Dept Genet, IL-91904 Jerusalem, Israel; Weizmann Inst Sci, Dept Chem, IL-76100 Rehovot, Israel
Identifiers:ISI:000177978800008 [ID No:1]
ISSN:1047-8477 [ID No:2]
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