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The selective elimination of messenger RNA underlies the mitosis-meiosis switch in fission yeast.

Yamamoto M - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2010)

Bottom Line: Meiosis-inducing signals in this microbe emanating from environmental conditions including the nutrient status converge on the activity of an RRM-type RNA-binding protein, Mei2.Fission yeast contains an RNA degradation system that selectively eliminates meiosis-specific mRNAs during the mitotic cell cycle.Mmi1, a novel RNA-binding protein of the YTH-family, is essential for this process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan. yamamoto@biochem.s.u-tokyo.ac.jp

ABSTRACT
The cellular programs for meiosis and mitosis must be strictly distinguished but the mechanisms controlling the entry to meiosis remain largely elusive in higher organisms. In contrast, recent analyses in yeast have shed new light on the mechanisms underlying the mitosis-meiosis switch. In this review, the current understanding of these mechanisms in the fission yeast Schizosaccharomyces pombe is discussed. Meiosis-inducing signals in this microbe emanating from environmental conditions including the nutrient status converge on the activity of an RRM-type RNA-binding protein, Mei2. This protein plays pivotal roles in both the induction and progression of meiosis and has now been found to govern the meiotic program in a quite unexpected manner. Fission yeast contains an RNA degradation system that selectively eliminates meiosis-specific mRNAs during the mitotic cell cycle. Mmi1, a novel RNA-binding protein of the YTH-family, is essential for this process. Mei2 tethers Mmi1 and thereby stabilizes the transcripts necessary for the progression of meiosis.

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Signal transduction pathways that regulate the initiation of meiosis in fission yeast. Four pathways that regulate expression of the ste11 gene, which encodes a transcription factor crucial for sexual development, are schematically depicted. From left to right: The cAMP pathway response to glucose; the TORC1 pathway response to nitrogen sources; the MAP kinase pathway response to mating pheromones; and the MAP kinase pathway response to environmental stresses. The former two pathways down-regulate, whereas the latter two up-regulate, ste11 expression. Reproduced from Ref. 25 with some modifications.
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fig02: Signal transduction pathways that regulate the initiation of meiosis in fission yeast. Four pathways that regulate expression of the ste11 gene, which encodes a transcription factor crucial for sexual development, are schematically depicted. From left to right: The cAMP pathway response to glucose; the TORC1 pathway response to nitrogen sources; the MAP kinase pathway response to mating pheromones; and the MAP kinase pathway response to environmental stresses. The former two pathways down-regulate, whereas the latter two up-regulate, ste11 expression. Reproduced from Ref. 25 with some modifications.

Mentions: Signal cascades emanating from environmental stimuli and leading to the initiation of meiosis have now been elucidated in fission yeast. Four signal transduction pathways have been shown to be important for the induction of meiosis and respond, respectively, to the carbon source, the nitrogen source, the mating pheromone, and stress stimuli (Fig. 2). A shift from a glucose-based rich medium to a poor carbon source results in a lowered intracellular cAMP level in fission yeast, followed by the downregulation of cAMP-dependent protein kinase (PKA). This lowered PKA activity stimulates transcription of the ste11 gene, which encodes an HMG-type transcription factor pivotal for sexual development.11–16)


The selective elimination of messenger RNA underlies the mitosis-meiosis switch in fission yeast.

Yamamoto M - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2010)

Signal transduction pathways that regulate the initiation of meiosis in fission yeast. Four pathways that regulate expression of the ste11 gene, which encodes a transcription factor crucial for sexual development, are schematically depicted. From left to right: The cAMP pathway response to glucose; the TORC1 pathway response to nitrogen sources; the MAP kinase pathway response to mating pheromones; and the MAP kinase pathway response to environmental stresses. The former two pathways down-regulate, whereas the latter two up-regulate, ste11 expression. Reproduced from Ref. 25 with some modifications.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037521&req=5

fig02: Signal transduction pathways that regulate the initiation of meiosis in fission yeast. Four pathways that regulate expression of the ste11 gene, which encodes a transcription factor crucial for sexual development, are schematically depicted. From left to right: The cAMP pathway response to glucose; the TORC1 pathway response to nitrogen sources; the MAP kinase pathway response to mating pheromones; and the MAP kinase pathway response to environmental stresses. The former two pathways down-regulate, whereas the latter two up-regulate, ste11 expression. Reproduced from Ref. 25 with some modifications.
Mentions: Signal cascades emanating from environmental stimuli and leading to the initiation of meiosis have now been elucidated in fission yeast. Four signal transduction pathways have been shown to be important for the induction of meiosis and respond, respectively, to the carbon source, the nitrogen source, the mating pheromone, and stress stimuli (Fig. 2). A shift from a glucose-based rich medium to a poor carbon source results in a lowered intracellular cAMP level in fission yeast, followed by the downregulation of cAMP-dependent protein kinase (PKA). This lowered PKA activity stimulates transcription of the ste11 gene, which encodes an HMG-type transcription factor pivotal for sexual development.11–16)

Bottom Line: Meiosis-inducing signals in this microbe emanating from environmental conditions including the nutrient status converge on the activity of an RRM-type RNA-binding protein, Mei2.Fission yeast contains an RNA degradation system that selectively eliminates meiosis-specific mRNAs during the mitotic cell cycle.Mmi1, a novel RNA-binding protein of the YTH-family, is essential for this process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan. yamamoto@biochem.s.u-tokyo.ac.jp

ABSTRACT
The cellular programs for meiosis and mitosis must be strictly distinguished but the mechanisms controlling the entry to meiosis remain largely elusive in higher organisms. In contrast, recent analyses in yeast have shed new light on the mechanisms underlying the mitosis-meiosis switch. In this review, the current understanding of these mechanisms in the fission yeast Schizosaccharomyces pombe is discussed. Meiosis-inducing signals in this microbe emanating from environmental conditions including the nutrient status converge on the activity of an RRM-type RNA-binding protein, Mei2. This protein plays pivotal roles in both the induction and progression of meiosis and has now been found to govern the meiotic program in a quite unexpected manner. Fission yeast contains an RNA degradation system that selectively eliminates meiosis-specific mRNAs during the mitotic cell cycle. Mmi1, a novel RNA-binding protein of the YTH-family, is essential for this process. Mei2 tethers Mmi1 and thereby stabilizes the transcripts necessary for the progression of meiosis.

Show MeSH
Related in: MedlinePlus