Elf-1 contributes to the function of the complex interleukin (IL)-2-responsive enhancer in the mouse IL-2 receptor alpha gene.

Abstract

Lymphocytes regulate their responsiveness to IL-2 through the transcriptional control of the IL-2R alpha gene, which encodes a component of the high affinity IL-2 receptor. In the mouse IL-2R alpha gene this control is exerted via two regulatable elements, a promoter proximal region, and an IL-2-responsive enhancer (IL-2rE) 1.3 kb upstream. In vitro and in vivo functional analysis of the IL-2rE in the rodent thymic lymphoma-derived, CD4- CD8- cell line PC60 demonstrated that three separate elements, sites I, II, and III, were necessary for IL-2 responsiveness; these three sites demonstrate functional cooperation. Site III contains a consensus binding motif for members of the Ets family of transcription factors. Here we demonstrate that Elf-1, an Ets-like protein, binds to site III and participates in IL-2 responsiveness. In vitro site III forms a complex with a protein constitutively present in nuclear extracts from PC60 cells as well as from normal CD4- CD8- thymocytes. We have identified this molecule as Elf-1 according to a number of criteria. The complex possesses an identical electrophoretic mobility to that formed by recombinant Elf-1 protein and is super-shifted by anti-Elf-1 antibodies. Biotinylated IL-2rE probes precipitate Elf-1 from PC60 extracts provided site III is intact and both recombinant and PC60-derived proteins bind with the same relative affinities to different mutants of site III. In addition, by introducing mutations into the core of the site III Ets-like motif and comparing the corresponding effects on the in vitro binding of Elf-1 and the in vivo IL-2rE activity, we provide strong evidence that Elf-1 is directly involved in IL-2 responsiveness. The nature of the functional cooperativity observed between Elf-1 and the factors binding sites I and II remains unresolved; experiments presented here however suggest that this effect may not require direct interactions between the proteins binding these three elements.

• Authors: I Serdobova, M Pla, P Reichenbach, P Sperisen, J Ghysdael, A Wilson, J Freeman, M Nabholz
• Journal: The Journal of experimental medicine (J Exp Med) Vol. 185 Issue 7 Pg. 1211-21 (Apr 07 1997) ISSN: 0022-1007 [Print] United States
• PMID: 9104808 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA-Binding Proteins
• ELF1 protein, human
• Elf1 protein, mouse
• Ephrin-A2
• Interleukin-2
• Nuclear Proteins
• Proto-Oncogene Proteins
• Proto-Oncogene Proteins c-ets
• Receptors, Interleukin-2
• Transcription Factors

Topics

• Animals
• Base Sequence
• Binding Sites
• DNA-Binding Proteins (genetics, metabolism)
• Enhancer Elements, Genetic
• Ephrin-A2
• Interleukin-2 (pharmacology)
• Mice
• Molecular Sequence Data
• Mutation
• Nuclear Proteins (metabolism)
• Protein Binding
• Proto-Oncogene Proteins (genetics)
• Proto-Oncogene Proteins c-ets
• Receptors, Interleukin-2 (genetics)
• T-Lymphocytes (metabolism)
• Transcription Factors (genetics, metabolism)
• Tumor Cells, Cultured