Fission yeast Prp4p kinase regulates pre-mRNA splicing by phosphorylating a non-SR-splicing factor

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Pre-mRNA splicing is a fundamental process in gene expression.
• The spliceosome is a large molecular complex responsible for splicing.
• Regulation of spliceosome assembly and function is crucial for cellular processes.

Purpose of the Study:

• To investigate the role of Prp4p kinase in pre-mRNA splicing and cell cycle progression.
• To elucidate the interaction of Prp4p with other splicing factors.
• To understand how Prp4p kinase activity influences spliceosome formation.

Main Methods:

• In vivo studies of Prp4p kinase activity and its effect on cell cycle.
• Genetic interaction analysis with non-SR splicing factors (Prp1p, Prp5p).
• In vitro phosphorylation assays using bacterially produced Prp1p.
• Yeast two-hybrid system for protein-protein interaction studies.
• In vivo labeling studies to assess Prp1p phosphorylation in a mutant strain.

Main Results:

• Prp4p kinase activity is required for pre-mRNA splicing in vivo.
• Loss of Prp4p activity impairs G1-S and G2-M cell cycle progression.
• Prp4p interacts genetically and physically with non-SR splicing factors Prp1p and Prp5p.
• Prp4p phosphorylates Prp1p in vitro, and Prp1p phosphorylation is altered in vivo in a prp4 mutant.
• Evidence suggests Prp4p kinase controls spliceosome formation by targeting non-SR splicing factors.

Conclusions:

• Prp4p kinase plays a critical role in regulating pre-mRNA splicing and cell cycle progression.
• Prp4p kinase activity is essential for the proper function of non-SR splicing factors.
• These findings highlight Prp4p's importance in controlling spliceosome assembly and targeting.