Cell cycle regulation of cdc25C transcription is mediated by the periodic repression of the glutamine-rich activators NF-Y and Sp1.
The late S/G2-specific transcription of the human cdc25C gene is dependent on an initiator-proximal repressor element (CDE) and an upstream activating sequence (UAS) of undefined nature. We now show that these upstream sequences harbour multiple in vivo protein binding sites that interact with transcriptional activators and form separable, context-independent functional modules. Major components of the UAS are a bona fide Sp1 site and three direct sequence repeats (Yc-boxes). The Yc-boxes interact with the CCAAT-box binding protein NF-Y and are critically dependent on synergistic interactions for efficient transcription activation. The NF-Y complexes, as well as Sp1, are constitutive activators, whose activation function is periodically repressed through the CDE. These observations indicate that the cell cycle regulation of cdc25C transcription is mainly due to the CDE-mediated repression of glutamine-rich activators.
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D020687:cdc25 Phosphatases
D022762:CCAAT-Enhancer-Binding Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D010749:Phosphoprotein Phosphatases; D020687:cdc25 Phosphatases