Representative cancer-associated U2AF2 mutations alter RNA interactions and splicing.

Area of Science:

• Molecular Biology
• Cancer Genomics
• Structural Biology

Background:

• High-throughput sequencing identifies recurrent mutations in splicing factors in various cancers.
• The U2AF2 protein is essential for pre-mRNA splicing, recognizing polypyrimidine tracts to initiate spliceosome assembly.

Purpose of the Study:

• To investigate the structural and functional consequences of acquired U2AF2 mutations (N196K and G301D) found in leukemia and solid tumors.
• To understand how these mutations impact U2AF2's RNA-binding affinity and splicing activity.

Main Methods:

• Determined crystal structures of wild-type (WT) U2AF2 and its N196K and G301D mutants bound to a polypyrimidine tract.
• Assessed RNA-binding affinity of WT and mutant U2AF2 proteins.
• Evaluated the effect of mutant U2AF2 expression on minigene and endogenous transcript splicing.

Main Results:

• The N196K mutation stabilizes an open U2AF2 conformation, increasing RNA-binding affinity.
• The G301D mutation leads to unfavorable proximity to RNA, decreasing RNA-binding affinity.
• Both N196K and G301D mutations were shown to alter splicing of minigene and endogenous transcripts.

Conclusions:

• Acquired U2AF2 mutations N196K and G301D directly impact splicing factor function.
• These mutations can dysregulate gene expression, potentially contributing to neoplastic transformation and cancer progression.