Abstract
Diploid yeast cells switch from mitosis to meiosis when starved of essential nutrients. While G1 cyclins play a key role in initiating the mitotic cell cycle, entry into meiosis depends on Ime1, a transcriptional activator regulated by both nutritional and cell-type signals. We show here that G1 cyclins downregulate IME1 transcription and prevent the accumulation of the Ime1 protein within the nucleus, which results in repression of early-meiotic gene expression. As G1-cyclin deficient cells do not require nutrient starvation to undergo meiosis, G1 cyclin would exert its role by transmitting essential nutritional signals to Ime1 function. The existence of a negative cross-talk mechanism between mitosis and meiosis may help explain why these two developmental options are incompatible in budding yeast.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Nucleus / physiology
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Culture Media
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Cyclins / genetics
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Cyclins / physiology*
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Fungal Proteins / genetics
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Fungal Proteins / physiology*
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G1 Phase / genetics
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G1 Phase / physiology*
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Gene Expression
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Genes, Fungal
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Meiosis / genetics
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Meiosis / physiology*
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Mitosis / genetics
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Mitosis / physiology*
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Nuclear Proteins / genetics
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Nuclear Proteins / physiology*
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S Phase / genetics
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S Phase / physiology
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Saccharomyces cerevisiae / cytology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / physiology*
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Saccharomyces cerevisiae Proteins*
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Signal Transduction
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Trans-Activators / genetics
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Trans-Activators / physiology
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Transcription Factors*
Substances
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CLN1 protein, S cerevisiae
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CLN2 protein, S cerevisiae
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CLN3 protein, S cerevisiae
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Culture Media
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Cyclins
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Fungal Proteins
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IME1 protein, S cerevisiae
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Nuclear Proteins
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Saccharomyces cerevisiae Proteins
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Trans-Activators
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Transcription Factors