U6atac snRNA stem-loop interacts with U12 p65 RNA binding protein and is functionally interchangeable with the U12...

Area of Science:

• Molecular Biology
• RNA Biology
• Genetics

Background:

• The U12-dependent spliceosome is crucial for splicing specific introns.
• Interactions between U6atac and U12 small nuclear RNAs (snRNAs) are key to spliceosome formation.
• Previous studies identified a targeting activity in the U6atac snRNA 3' stem-loop.

Purpose of the Study:

• To analyze the structure-function relationship of the U6atac 3' stem-loop in U12-dependent splicing.
• To investigate the role of protein p65 in U6atac and U12 snRNA interactions.
• To explore the evolutionary conservation and functional compatibility of U6atac 3' ends across species.

Main Methods:

• Structure-function analysis of U6atac 3' stem-loop substructures.
• In vivo splicing assays.
• Binary splice site mutation suppressor assays.
• Cross-species compatibility tests of U6atac 3' ends.

Main Results:

• A substructure within the U6atac 3' stem-loop is essential for U12-dependent splicing.
• The protein p65 binds to the U6atac 3' stem-loop.
• The U6atac distal 3' stem-loop can functionally replace the p65-binding stem-loop of U12 snRNA.
• U6atac 3' ends from diverse species are compatible with the human spliceosome, indicating evolutionary relatedness.

Conclusions:

• RNA-RNA and RNA-protein interactions in the minor spliceosome exhibit significant plasticity.
• The U6atac 3' stem-loop plays a critical, adaptable role in U12-dependent splicing.
• Minor spliceosome components show greater evolutionary flexibility compared to the major spliceosome.