Structural characterization of the fission yeast U5.U2/U6 spliceosome complex.

Ohi MD, Ren L, Wall JS, Gould KL, Walz T
Proc Natl Acad Sci U S A. 2007 104 (9): 3195-200

PMID: 17360628 · PMCID: PMC1805518 · DOI:10.1073/pnas.0611591104

The spliceosome is a dynamic macromolecular machine that catalyzes the excision of introns from pre-mRNA. The megadalton-sized spliceosome is composed of four small nuclear RNPs and additional pre-mRNA splicing factors. The formation of an active spliceosome involves a series of regulated steps that requires the assembly and disassembly of large multiprotein/RNA complexes. The dynamic nature of the pre-mRNA splicing reaction has hampered progress in analyzing the structure of spliceosomal complexes. We have used cryo-electron microscopy to produce a 29-A density map of a stable 37S spliceosomal complex from the genetically tractable fission yeast, Schizosaccharomyces pombe. Containing the U2, U5, and U6 snRNAs, pre-mRNA splicing intermediates, U2 and U5 snRNP proteins, the Nineteen Complex (NTC), and second-step splicing factors, this complex closely resembles in vitro purified mammalian C complex. The density map reveals an asymmetric particle, approximately 30 x 20 x 18 nm in size, which is composed of distinct domains that contact each other at the center of the complex.

MeSH Terms (10)

Cryoelectron Microscopy Models, Molecular Multiprotein Complexes Protein Conformation Protein Structure, Tertiary Reverse Transcriptase Polymerase Chain Reaction Ribonucleoproteins, Small Nuclear RNA Splicing Schizosaccharomyces Spliceosomes

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