Role of a proximal NF-Y binding promoter element in S phase-specific expression of mouse ribonucleotide reductase R2 gene.
Cell cycle-regulated transcription of the R2 gene of mouse ribonucleotide reductase was earlier shown to be controlled at the level of elongation by an S phase-specific release from a transcriptional block. However, the R2 promoter is activated very early when quiescent cells start to proliferate, and this activation is dependent on three upstream sequences located nucleotide -672 to nucleotide -527 from the transcription start. In this study, we use R2-luciferase reporter gene constructs and gel shift assays to demonstrate that, in addition to the upstream sequences, a proximal CCAAT element specifically binding the transcription factor NF-Y is required for continuous activity of the R2 promoter through the S phase. When the CCAAT element is deleted or mutated, promoter activity induced by the upstream elements decays before cells enter S phase, and the transcriptional block is released. This is a clear example of how changing of a proximal sequence element can alter not only the quantitative but also the qualitative response to upstream transcription activation domains.
Filatov
D
D
Department of Medical Biochemistry and Biophysics, Umea University, Sweden.
Thelander
L
L
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011401:Promoter Regions, Genetic; D012264:Ribonucleotide Reductases / Q000235:genetics*; D016196:S Phase; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D014157:Transcription Factors; D012264:Ribonucleotide Reductases