The ubiquitous transcription factor NF-Y positively regulates the transcription of human p27Kip1 through a CCAAT box located in the 5-upstream region of the p27Kip1 gene.
Abnormally low levels of the cyclin-dependent kinase inhibitor p27Kip1 are found frequently in human carcinomas, and these levels correlate directly with both histological aggressiveness and patient mortality. p27Kip1 is haplo-insufficient for tumor suppression. Thus, p27Kip1 may be a useful molecule for the development of cancer therapies. To know the possible mechanisms underlying transcriptional control, we previously cloned the promoter region of human p27Kip1 gene. We report here the characterization of the 5'-regulatory region of the human p27Kip1 gene. Promoter analysis using 5'-deletion mutants revealed that a 39-bp region between -549 and -511 was required for maximal promoter activity. Point mutation analysis revealed that a CCAAT box within this region was essential for promoter activity. Gel shift assays and cotransfection experiments using a dominant negative form of the NF-Y transcription factor showed that NF-Y directly regulates p27Kip1 transcription through this CCAAT box. This finding might provide a clue to approach the mechanism of tumorigenesis.
Kamiyama
J
J
Department of Preventive Medicine, Kyoto Prefectural University of Medicine, Japan.
Inoue
T
T
Ohtani-Fujita
N
N
Minami
S
S
Yamagishi
H
H
Sakai
T
T
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins; D018797:Cell Cycle Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015342:DNA Probes / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005809:Genes, Regulator; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D022762:CCAAT-Enhancer-Binding Proteins; D018797:Cell Cycle Proteins; D015342:DNA Probes; D004268:DNA-Binding Proteins; D008869:Microtubule-Associated Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA