piE2F6/i is widely expressed in human tissues and cell lines. Recent studies have demonstrated its involvement in developmental patterning and in the regulation of various genes implicated in chromatin remodelling. Despite a growing number of studies, nothing is really known concerning the iE2F6/i expression regulation. To understand how cells control iE2F6/i expression, we analysed the activity of the previously cloned promoter region of the human iE2F6/i gene. DNase I footprinting, gel electrophoreticmobility shift, transient transfection and site-directed mutagenesis experiments allowed the identification of two functional NRF-1/α-PAL (nuclear respiratory factor-1/α-palindrome-binding protein)-binding sites within the human iE2F6/i core promoter region, which are conserved in the mouse and rat iE2F6/i promoter region. Moreover, ChIP (chromatin immunoprecipitation) analysis demonstrated that overexpressed NRF-1/α-PAL is associated iin vivo/i with the iE2F6/i promoter. Furthermore, overexpression of full-length NRF-1/α-PAL enhanced iE2F6/i promoter activity, whereas expression of its dominant-negative form reduced the promoter activity. Our results indicate that NRF-1/α-PAL is implicated in the regulation of basal iE2F6/i gene expression./p
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