In vitro transcriptional activation of p21 promoter by p53.

The tumor suppressor p53 can control cell growth by inducing cell cycle arrest. This is effected, at least in part, by transcriptional activation of p21 gene, a cell cycle inhibitor. Here in vitro transcription assay for p21 has been established. The assay recapitulates activation of p21 promoter mediated by p53 in vitro. Thus this in vitro assay will allow to study how transcriptional regulation of p21 can be linked to cell cycle controls during development and neoplastic transformation processes.