SNEV is an evolutionarily conserved splicing factor whose oligomerization is necessary for spliceosome assembly

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• The human protein SNEV (Spliceosome Associated Factor) was identified as downregulated in replicatively senescent cells.
• Sequence homology suggested SNEV might be the human orthologue of the yeast splicing factor Prp19, implying a role in pre-mRNA splicing.

Purpose of the Study:

• To determine the function of the human protein SNEV.
• To confirm if SNEV is the orthologue of yeast Prp19 and investigate its role in pre-mRNA splicing.
• To elucidate the role of SNEV self-interaction in spliceosome function.

Main Methods:

• Gene complementation studies using a temperature-sensitive yeast mutant.
• Immunodepletion of SNEV from human HeLa nuclear extracts.
• Analysis of SNEV protein-protein interactions and mapping of self-interaction domains.
• In vitro splicing assays and spliceosome assembly studies.

Main Results:

• A human-yeast chimera of SNEV restored the wild-type phenotype in the yeast mutant, confirming its orthologous function.
• SNEV immunodepletion significantly decreased in vitro pre-mRNA splicing efficiency in human extracts.
• SNEV self-interacts, with the domain mapped to amino acids 56-74.
• Synthetic peptides from the SNEV self-interaction domain inhibited in vitro splicing by disrupting spliceosome formation and stability.

Conclusions:

• SNEV is the human orthologue of yeast PRP19 and plays a crucial role in pre-mRNA splicing.
• Homo-oligomerization of SNEV is essential for spliceosome assembly and stability in human cells.
• These findings highlight SNEV's importance in spliceosome dynamics and cellular senescence.