title: The pT alpha promoter and enhancer are direct targets for transactivation by E box-binding proteins.
abstract: The pre-T alpha (pT alpha) gene encodes a protein that forms the pre-TCR together with the newly expressed TCR beta chain during a defined stage of early T cell development. The restricted expression of this gene has been suggested to depend on a promoter and an enhancer element containing E boxes, which are potential binding sites for basic helix-loop-helix (bHLH) proteins. We here report that increased expression of E47 and E12 mRNA in CD4(-)CD8(-)TCR(-) thymocytes correlates with the initiation of pT alpha transcription. Furthermore, electrophoretic mobility shift assays suggested that E47 binds directly to both the pT alpha promoter and enhancer in vitro. Ectopic expression of E47 in non-lymphoid HeLa cells resulted in a dose- and template-dependent activation of these control elements. In addition to this, ectopic expression of E47 in combination with the ets-protein Pu.1 and/or the Pu.1-interacting protein(Pip-1), resulted in a synergistic effect on the activity of the pT alpha control elements. Thus, we suggest that E47, Pu.1 and Pip-1 are directly involved in the regulation of pT alpha expression in early T cell development.
authors.affiliation: Section for Immunology, Department of Cell and Molecular Biology, Lund University, Lund, Sweden. karin.Petersson@immuno.lu.se
authors.forename: Karin
authors.initials: K
authors.lastname: Petersson
authors.forename: Fredrik
authors.initials: F
authors.lastname: Ivars
authors.forename: Mikael
authors.initials: M
authors.lastname: Sigvardsson
mesh_terms: D000818:Animals; D001665:Binding Sites; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation / Q000235:genetics*; D019673:Genes, T-Cell Receptor alpha; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D050835:Interferon Regulatory Factors; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011498:Protein Precursors / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D051820:TCF Transcription Factors; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection; D000099232:Proto-Oncogene Protein Spi-1; D000099218:Interferon Regulatory Factor-4
chemical_list: D004268:DNA-Binding Proteins; D050835:Interferon Regulatory Factors; D011498:Protein Precursors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D051820:TCF Transcription Factors; D015534:Trans-Activators; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D000099232:Proto-Oncogene Protein Spi-1; D000099218:Interferon Regulatory Factor-4; C544912:TCF7L1 protein, human; C544913:Tcf7l1 protein, mouse