CHF : a novel factor binding to cyclin A CHR corepressor element

• Published in: Oncogene Vol. 18; no. 46; pp. 6222 - 6232
• Main Authors: PHILIPS, A, CHAMBEYRON, S, LAMB, N, VIE, A, BLANCHARD, J. M
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 04.11.1999; Nature Publishing Group
• Subjects: Animals; Base Sequence; Binding Sites; Binding, Competitive; Biological and medical sciences; Cdc2 protein; cdc25c gene; Cell cycle; Cell Cycle - genetics; Cell cycle, cell proliferation; Cell physiology; CHF protein; Chromatography, Gel; Cyclin A; Cyclin A - genetics; E2F protein; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Gene silencing; Homology; Humans; Hydroxyurea - pharmacology; Macromolecular Substances; Mice; Microinjection; Microinjections; Molecular and cellular biology; Molecular Sequence Data; Molecular Weight; MYB protein; Oligonucleotides; Promoter Regions, Genetic; Regulatory sequences; Regulatory Sequences, Nucleic Acid; Resting Phase, Cell Cycle; S phase; S Phase - drug effects; T-Lymphocytes - drug effects; T-Lymphocytes - metabolism; Transcription Factors - isolation & purification; Transcription Factors - metabolism; Transcription, Genetic; Human; Regulation(control); Cell line; Cell cycle; DNA binding protein; Molecular interaction; Regulatory sequence; Gene expression
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1203017

Cell cycle modulation of cyclin A expression is due to the periodic relief of a transcriptional repression mediated by a bipartite negative DNA regulatory region. The 5' element (Cell Cycle Responsive Element: CCRE; cell Cycle Dependent Element: CDE) is clearly occupied in a cyclic manner in vivo, whereas the 3' element, whose sequence is shared by B-myb, cdc25C and cdc2 genes (cell Cycle gene Homology Region: CHR), is involved in more subtle interactions. Mutation of either element results in complete deregulation of cyclin A promoter activity. Whereas some reports claim that E2F/DP can bind to the CCRE/CDE, the nature of the protein(s) interacting with the CHR is unknown. In the present work we have characterized an activity present in quiescent cells and absent in cells blocked in S phase, which binds specifically to cyclin A CHR, but not to B-myb, or to cdc25C, or to cdc2 CHRs. A 90 kD protein, named CHF (cyclin A CHR binding factor), has been identified through preparative electrophoresis and UV crosslinking experiments. In order to address in more functional terms the binding of CHF to cyclin A CHR, we developed in vitro and in vivo oligonucleotide competition assays. Both in vitro transcription and in vivo microinjection experiments demonstrate that a functional difference exists between the composite CCRE/CDE-CHR repressor regions of cell cycle regulated genes such as cyclin A and cdc25C.