The ubiquitous transcription factor NF-Y positively regulates the transcription of human p27(Kip1) through a CCAAT box located in the 5 '-upstream region of the p27(Kip1) gene

Abnormally low levels of the cyclin-dependent kinase inhibitor p27(Kip1) ar e found frequently in human carcinomas, and these levels correlate directly with both histological aggressiveness and patient mortality, p27(Kip1) is haplo-insufficient for tumor suppression. Thus, p27(Kip1) may be a useful m olecule for the development of cancer therapies. To know the possible mecha nisms underlying transcriptional control, me previously cloned the promoter region of human p27(Kip1) gene, We report here the characterization of the 5'-regulatory region of the human p27(Kip1) gene, Promoter analysis using 5'-deletion mutants revealed that a 39-bp region between -549 and -511 mas required for maximal promoter activity, Point mutation analysis revealed th at 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 p27(Ki p1) transcription through this CCAAT box. This finding might provide a clue to approach the mechanism of tumorigenesis, (C) 1999 Federation of Europea n Biochemical Societies.