Two short sequences have positive effects on the human p27(Kip1) gene transcription

The cyclin-dependent kinase (Cdk) inhibitor p27(Kip1) plays an important ro le in the progression from G1 to S phase in the cell cycle. To study the ac tivities of its promoter and other regulatory elements, we have cloned and characterized the 5'-flanking region of the human p27(Kip1) gene. This regi on, about 3 kb in length, is GC-rich and shares homology with that of the m ouse p27(Kip1) gene. Transcription start points (tsp) determined by the oli go-capping method are mapped in two regions, the cluster I (-479 to -403) a nd cluster II (-280 to -273). The cluster I was the primary functional site in transcription initiation. The luciferase activities of serial deletion mutants indicated that two short sequences (-581 to -557 and -556 to -526) had positive effects on transcription. The gel shift assay showed that fact ors in HeLa nuclear extract bound to these sequences. Spl was the major bin ding factor to the sequence of -556 to -526, wheres yet unidentified positi ve factors bound to the sequence of -581 to -557. (C) 1999 Elsevier Science B.V. All rights reserved.