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Fission yeast Prp4p kinase regulates pre-mRNA splicing by phosphorylating a non-SR-splicing factor
W Schwelnus1, K Richert, F Opitz
1Institute of Genetics, Technical University of Braunschweig, Germany.
Abstract:
We provide evidence that Prp4p kinase activity is required for pre-mRNA splicing in vivo and show that loss of activity impairs G1-S and G2-M progression in the cell cycle. Prp4p interacts genetically with the non-SR (serine/arginine) splicing factors Prp1p and Prp5p. Bacterially produced Prp1p is phosphorylated by Prp4p in vitro. Prp4p and Prp1p also interact in the yeast two-hybrid system. In vivo labelling studies using a strain with a mutant allele of the prp4 gene in the genetic background indicate a change in phosphorylation of the Prp1p protein. These results are consistent with the notion that Prp4p kinase is involved in the control of the formation of active spliceosomes, targeting non-SR splicing factors.
Insights
Prp4p kinase activity is essential for pre-mRNA splicing and cell cycle progression. This study shows Prp4p kinase targets non-SR splicing factors, controlling spliceosome formation.
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.