An Atomic Structure of the Human Spliceosome

Area of Science:

• Molecular Biology
• Structural Biology
• Genetics

Background:

• Understanding pre-mRNA splicing is crucial for deciphering gene expression.
• Detailed structural information of spliceosome intermediates is needed for mechanistic insights.

Purpose of the Study:

• To determine the cryo-electron microscopy (cryo-EM) structure of the human spliceosome C* complex.
• To elucidate the structural basis of exon ligation during pre-mRNA splicing.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was used to obtain the structure.
• High-resolution structural analysis of the spliceosome C* complex.

Main Results:

• The structure of the human spliceosome C* complex was resolved at 3.76 Å resolution.
• Identified roles of splicing factors Prp17, Slu7, RBM22, PRKRIP1, Prp22, and the exon junction complex (EJC).
• Revealed the path of the intron lariat through a charged channel and the interaction network stabilizing the active site.

Conclusions:

• The structure provides key mechanistic insights into the exon ligation step of pre-mRNA splicing.
• Highlights the precise organization of factors and RNA for efficient splicing.
• Advances our understanding of the spliceosome's dynamic conformational changes.