Regulation of the Pur-alpha promoter by E2F-1.
Puralpha is a ubiquitously expressed multifunctional nucleic acid-binding protein that is involved in many cellular processes including transcriptional regulation, the cell cycle, oncogenic transformation, and post-natal brain development. Previously, Puralpha protein was found to bind to E2F-1, inhibit E2F-1 transcriptional activity, and reverse the effects of ectopic E2F-1 expression on cell growth. Also Puralpha binds to a GC/GA-rich sequence within its own promoter and inhibits gene expression, that is, Puralpha is autoregulated. We now report that the Puralpha promoter (pPuralpha) is induced by E2F-1 and that this activity maps to a consensus E2F-1 binding motif that is juxtaposed to the Puralpha binding site. Deletion mutants of the E2F-1 protein showed that the region between amino acid residues 88-241 is important for this activity. E2F-1-associated activation of the pPuralpha was inhibited by co-expression of Puralpha, pRb, and an RNA species with specific binding to E2F-1. Chromatin immunoprecipitation (ChIP) assay using primers that flanked the juxtaposed Puralpha and E2F-1 binding sites verified the presence of Puralpha and E2F-1 on the pPuralpha in vivo. In a Tet-inducible cell line, Puralpha delayed cell cycle progression. Thus, E2F-1 and Puralpha interplay appears to be involved in the regulation of Puralpha expression and the cell cycle.
Darbinian
Nune
N
Center for Neurovirology, Department of Neuroscience, Temple University School of Medicine, Philadelphia, Pennsylvania 19122, USA.
White
Martyn K
MK
Khalili
Kamel
K
D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000235:genetics*; D050687:E2F1 Transcription Factor / Q000378:metabolism*; D016193:G1 Phase; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011485:Protein Binding; D020218:Response Elements / Q000235:genetics*; D016160:Retinoblastoma Protein / Q000378:metabolism; D017384:Sequence Deletion; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism
D020121:5' Untranslated Regions; D004268:DNA-Binding Proteins; D050687:E2F1 Transcription Factor; D009419:Nerve Tissue Proteins; C121485:Pura protein, mouse; D016160:Retinoblastoma Protein; D013762:Tetrahydrofolate Dehydrogenase