Changes in a SWI4,6-DNA-binding complex occur at the time of HO gene activation in yeast.
The yeast HO gene is transcribed transiently during G1 as cells undergo START. START-specific HO activation requires two proteins, SWI4 and SWI6, which act via a motif (CACGA4) repeated up to 10 times within the URS2 region of the HO promoter. We identified a DNA-binding activity containing SWI4 and SWI6 that recognizes the CACGA4 sequences within URS2. Two forms of SWI4,6-DNA complexes called L and U can be distinguished by their electrophoretic mobility. L complexes can be detected at all stages of the cell cycle, but U complexes are only detected in cells that have undergone START. The formation of U complexes may be the trigger of HO activation. The SWI6 protein is concentrated in the nucleus throughout G1, but at some point in S or G2 significant amounts accumulate in the cytoplasm. This change in cellular location of the SWI6 protein might contribute to the turnoff of HO transcription after cells have undergone START.
Research Institute of Molecular Pathology, Vienna, Austria.
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Taba
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Muroff
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Lydall
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Tebb
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Nasmyth
D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D005800:Genes, Fungal / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C062214:SWI4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011494:Protein Kinases; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific