Arginine-serine-rich domains bound at splicing enhancers contact the branchpoint to promote prespliceosome assembly
Program in Molecular Medicine; Program in Gene Function and Expression
Medical Subject Headings
Arginine; Base Sequence; Binding Sites; Enhancer Elements, Genetic; Hela Cells; Humans; Molecular Sequence Data; Protein Binding; Protein Structure, Tertiary; RNA Splicing; RNA, Messenger; RNA-Binding Proteins; Recombinant Fusion Proteins; Serine; Spliceosomes
Biochemistry, Biophysics, and Structural Biology | Genetics and Genomics
Exonic splicing enhancers (ESEs) are required for splicing of certain pre-mRNAs and function by providing binding sites for serine-arginine (SR) proteins, which contain an arginine-serine-rich (RS) domain. How an RS domain bound at the ESE promotes splicing is poorly understood. We have developed an RNA-protein crosslinking procedure to identify the target of the ESE-bound RS domain. Using this approach, we show that the ESE-bound RS domain specifically contacts the pre-mRNA branchpoint. The interaction between the ESE-bound RS domain and the branchpoint occurs in the prespliceosome and is dependent upon the same splicing signals, biochemical factors, and reaction conditions required to support prespliceosome assembly. Analysis of RS domain mutants demonstrates that the ability to interact with the branchpoint, to promote prespliceosome assembly, and to support splicing are related activities. We conclude that the ESE-bound RS domain functions by contacting the branchpoint to promote prespliceosome assembly.
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Citation: Mol Cell. 2004 Feb 13;13(3):367-76.