Related Experiment Videos
Analysis of the structural genes encoding M-factor in the fission yeast Schizosaccharomyces pombe: identification of
S Kjaerulff1, J Davey, O Nielsen
1Department of Genetics, University of Copenhagen, Denmark.
Abstract:
We previously identified two genes, mfm1 and mfm2, with the potential to encode the M-factor mating pheromone of the fission yeast Schizosaccharomyces pombe (J. Davey, EMBO J. 11:951-960, 1992), but further analysis revealed that a mutant strain lacking both genes still produced active M-factor. Here we describe the isolation and characterization of a third M-factor gene, mfm3. A mutant lacking all three genes fails to produce M-factor, indicating that all functional M-factor genes now have been identified. The triple mutant exhibits an absolute mating defect in M cells, a defect that is not rescued by addition of exogenous M-factor. A mutational analysis reveals that all three mfm genes contribute to the production of M-factor. Their transcription is limited to M cells and requires the mat1-Mc and ste11 gene products. Each gene is induced when the cells are starved of nitrogen and further induced by a pheromone signal. Additionally, the signal transduction machinery associated with the pheromone response is required for transcription of the mfm genes in both stimulated and unstimulated cells.
Insights
Researchers identified mfm3, the third gene for M-factor pheromone in Schizosaccharomyces pombe. A triple mutant lacking mfm1, mfm2, and mfm3 shows a complete mating defect, confirming all M-factor genes are found.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- The M-factor pheromone is crucial for mating in the fission yeast Schizosaccharomyces pombe.
- Previous studies identified mfm1 and mfm2 as potential M-factor genes, but a double mutant still produced active M-factor.
Purpose of the Study:
- To identify the complete set of genes responsible for M-factor production in Schizosaccharomyces pombe.
- To characterize the function and regulation of the identified M-factor genes.
Main Methods:
- Gene isolation and characterization of mfm3.
- Construction and analysis of a triple mutant lacking mfm1, mfm2, and mfm3.
- Mutational analysis of mfm gene function.
- Analysis of mfm gene transcription regulation.
Main Results:
- The mfm3 gene was isolated and characterized as a third component of M-factor.
- A triple mutant lacking mfm1, mfm2, and mfm3 failed to produce M-factor, indicating all functional genes were identified.
- The triple mutant displayed an absolute mating defect.
- All three mfm genes contribute to M-factor production.
- mfm gene transcription is specific to M cells and regulated by mat1-Mc, ste11, nitrogen starvation, and pheromone signaling.
Conclusions:
- The genes mfm1, mfm2, and mfm3 encode the M-factor mating pheromone in Schizosaccharomyces pombe.
- The identified genes are essential for mating and their transcription is tightly regulated by mating-type and pheromone response pathways.