SF3B1 association with chromatin determines splicing outcomes

Area of Science:

• Molecular Biology
• Genetics
• Chromatin Biology

Background:

• The precise mechanism of splicing factor targeting to pre-mRNA remains unclear.
• Chromatin organization differences between exons and introns may play a role.

Purpose of the Study:

• To investigate the role of chromatin organization in splice site recognition.
• To determine if SF3B1 associates with chromatin and affects splicing.

Main Methods:

• Proteomic analysis
• Co-immunoprecipitation
• Sedimentation assays
• Chromatin immunoprecipitation sequencing (ChIP-seq)
• RNA sequencing (RNA-seq)

Main Results:

• SF3B1 (a U2 snRNP splicing factor) strongly associates with nucleosomes.
• SF3B1 specifically binds to nucleosomes located at exonic positions.
• SF3B1 binding is enriched over short exons with differential GC content.
• Disrupting SF3B1-nucleosome binding impacts splicing of these exons.

Conclusions:

• SF3B1's association with nucleosomes is functionally important for splice site recognition.
• SF3B1 utilizes chromatin structure information for splicing decisions.