The carboxy-terminal tail of the homeo domain protein alpha 2 is required for function with a second homeo domain protein.
The homeo domain protein alpha 2 from Saccharomyces cerevisiae has two roles in the a/alpha cell: With MCM1, alpha 2 turns off transcription of a-specific genes; with a1 (a second homeo domain protein), alpha 2 represses transcription of haploid-specific genes. From the carboxy-terminal side of the alpha 2 homeo domain extends an unstructured 22-amino-acid residue tail. In this paper we show that the carboxy-terminal tail of alpha 2 is required for formation of a stable a1/alpha 2-operator complex and is thus required for a1/alpha 2-mediated repression of transcription. In contrast, the tail is dispensable for alpha 2/MCM1-mediated repression. These results indicate that a short, unstructured tail mediates the interaction between two homeo domain proteins.
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Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0502.
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D001483:Base Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005801:Genes, Homeobox; D017930:Genes, Reporter; D006238:Haploidy; D018398:Homeodomain Proteins; D026341:Minichromosome Maintenance 1 Protein; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic / Q000235:genetics; D010446:Peptide Fragments / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017421:Sequence Analysis; D017384:Sequence Deletion; D012697:Serine Endopeptidases / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D018398:Homeodomain Proteins; C062928:MATA2 protein, S cerevisiae; D026341:Minichromosome Maintenance 1 Protein; D010446:Peptide Fragments; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase