Abstract
S. cerevisiae cells exhibit asymmetric determination of cell fate. Cell division yields a mother cell, which is competent to transcribe the HO gene and switch mating type, and a daughter cell, which is not. We have isolated a mutant in which daughters transcribe HO and switch mating type. This mutation defines the ASH1 gene (asymmetric synthesis of HO). Deletion and overexpression of ASH1 cause reciprocal cell fate transformations: im ash1delta strains, daughters switch mating type as efficiently as mothers. Conversely, overexpression of ASH1 inhibits switching in mother cells. Ash1p has a zinc finger motif related to those of GATA transcriptional regulators. Ash1p is localized to the daughter nucleus in cells that have undergone nuclear division. Thus, Ash1p is a cell fate determinant that is asymmetrically localized to the daughter nucleus where it inhibits HO transcription.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Cloning, Molecular
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DNA-Binding Proteins*
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Deoxyribonucleases, Type II Site-Specific / biosynthesis*
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Deoxyribonucleases, Type II Site-Specific / genetics
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Ethyl Methanesulfonate
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Genes, Fungal*
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Genes, Mating Type, Fungal*
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Genotype
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Mitosis
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Models, Biological
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Molecular Sequence Data
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Mutagenesis
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Mutagens
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / chemistry
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Repressor Proteins*
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae Proteins*
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Sequence Homology, Amino Acid
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Transcription Factors / chemistry
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Transcription Factors / genetics*
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Transcription Factors / metabolism*
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Transcription, Genetic*
Substances
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ASH1 protein, S cerevisiae
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DNA-Binding Proteins
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Mutagens
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Recombinant Proteins
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Repressor Proteins
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Saccharomyces cerevisiae Proteins
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Transcription Factors
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Ethyl Methanesulfonate
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HO protein, S cerevisiae
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SCEI protein, S cerevisiae
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Deoxyribonucleases, Type II Site-Specific