第1162回生物科学セミナー

Splicing Snapshots: Cryo-EM Structures of the Spliceosome

Dr. Max Wilkinson(MRC Laboratory of Molecular Biology, University of Cambridge)

2017年06月29日(Thu)    13:00-14:00  理学部3号館 303号室   

Splicing is a fundamental step in eukaryotic gene expression, where non-coding introns are removed from messenger RNAs, and alternative splicing is a major contributor to proteome diversity in higher organisms. A large, dynamic protein-RNA complex called the spliceosome catalyses splicing by assembling on pre-mRNA substrates and performing two transesterification reactions. Although the spliceosome was discovered more than 30 years ago, it has defied structural characterisation by X-ray crystallography due to its low abundance and extreme flexibility. Recent developments in cryo-electron microscopy (cryo-EM), including new detectors and statistical image processing algorithms, have caused a revolution in structural biology. In this talk I will present near-atomic resolution cryo-EM structures of the spliceosome carrying out the two chemical steps of splicing. These structures reveal the architecture of this immense machine, the roles of step-specific splicing factors, and show how the entirely RNA-based active site performs catalysis.


参考文献
Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 Å resolution. Nature. 530(7590), p298-302 (2016)
Cryo-EM structure of the spliceosome immediately after branching. Nature. 537(7619), p197-201 (2016)