The yeast MUD2 protein: an interaction with PRP11 defines a bridge between commitment complexes and U2 snRNP addition

Area of Science:

• Molecular Biology
• Genetics
• RNA Splicing

Background:

• The spliceosome is a complex molecular machine responsible for RNA splicing in eukaryotes.
• Understanding the assembly and function of spliceosome components is critical for deciphering gene expression regulation.
• The yeast U1 RNA and metazoan splicing factor U2AF65 are key players in spliceosome assembly.

Purpose of the Study:

• To identify and characterize yeast genes involved in spliceosome assembly.
• To investigate the function of the MUD2 gene and its product (MUD2P) in pre-mRNA splicing.
• To explore the functional similarity between yeast MUD2P and metazoan U2AF65.

Main Methods:

• Characterization of yeast (Saccharomyces cerevisiae) mutants synthetic lethal with U1 RNA.
• Biochemical assays to determine MUD2P's interaction with pre-mRNA and spliceosome complexes.
• Genetic experiments to assess MUD2P's role in U2 snRNP addition.
• Two-hybrid system experiments to investigate protein-protein interactions.

Main Results:

• Identification of the yeast MUD2 gene with sequence similarity to metazoan U2AF65.
• MUD2P directly contacts pre-mRNA and is part of the early spliceosome commitment complex.
• MUD2P association with pre-mRNA is dependent on the branchpoint sequence.
• MUD2P influences U2 snRNP addition and interacts with U2 snRNP component PRP11P.

Conclusions:

• MUD2P is a functional component of the yeast spliceosome, involved in early assembly steps.
• The study reveals a specific inter-snRNP protein-protein contact (MUD2P-PRP11P) during spliceosome assembly.
• Findings support significant functional conservation of splicing factors between yeast and metazoans.