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Isolation of novel pre-mRNA splicing mutants of Schizosaccharomyces pombe
S Urushiyama1, T Tani, Y Ohshima
1Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
Abstract:
New prp (pre-mRNA processing) mutants of the fission yeast Schizosaccharomyces pombe were isolated from a bank of 700 mutants that were either temperature sensitive (ts-) or cold sensitive (cs-) for growth. The bank was screened by Northern blot analysis with probes complementary to S. pombe U6 small nuclear RNA (sn RNA), the gene for which has a splicesomal (mRNA-type) intron. We identified 12 prp mutants that accumulated the U6 snRNA precursor at the nonpermissive temperature. All such mutants were also found to have defects in an early step of TFIID pre-mRNA splicing at the nonpermissive temperature. Complementation analyses showed that seven of the mutants belong to six new complementation groups designated as prp8 and prp10-prp14, whereas the five other mutants were classified into the known complementation groups prp1, prp2 and prp3. Interestingly, some of the isolated prp mutants produced elongated cells at the nonpermissive temperature, which is a phenotype typical of cell division cycle (cdc) mutants. Based on these findings, we propose that some of the wild-type products from these prp+ genes play important roles in the cellular processes of pre-mRNA splicing and cell cycle progression.
Insights
Researchers identified new pre-mRNA processing (prp) mutants in fission yeast. These mutants accumulate U6 small nuclear RNA precursors and show defects in splicing, linking pre-mRNA processing to cell cycle progression.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Pre-mRNA processing is essential for gene expression.
- Fission yeast (Schizosaccharomyces pombe) is a model organism for studying fundamental cellular processes.
- Spliceosomal small nuclear RNAs (snRNAs) are critical components of the splicing machinery.
Purpose of the Study:
- To isolate and characterize new mutants defective in pre-mRNA processing in Schizosaccharomyces pombe.
- To investigate the roles of novel genes involved in U6 small nuclear RNA metabolism and splicing.
- To explore potential links between pre-mRNA processing and cell cycle regulation.
Main Methods:
- Screening of temperature-sensitive (ts-) and cold-sensitive (cs-) mutants.
- Northern blot analysis to detect U6 snRNA precursor accumulation.
- Complementation analysis to determine new complementation groups.
- Phenotypic analysis of cell morphology at non-permissive temperatures.
Main Results:
- Identified 12 new pre-mRNA processing (prp) mutants.
- Observed accumulation of U6 snRNA precursor in all identified mutants.
- Demonstrated defects in early TFIID pre-mRNA splicing steps.
- Discovered that some mutants exhibit cell elongation, a phenotype associated with cell division cycle (cdc) mutants.
- Established six new complementation groups (prp8, prp10-prp14) and classified others into known groups (prp1, prp2, prp3).
Conclusions:
- The identified prp genes are crucial for efficient pre-mRNA splicing, particularly U6 snRNA processing.
- Novel prp gene products play significant roles in both mRNA splicing and cell cycle progression.
- These findings highlight an intricate connection between RNA processing pathways and cell division in eukaryotes.