Interaction of STAT5 Dimers on Two Low Affinity Binding Sites Mediates Interleukin 2 (IL-2) Stimulation of IL-2 Receptor α Gene Transcription

IL-2 and long-term T cell activation induce physical and functional interaction between STAT5 and ETS transcription factors in human T cells

“…To characterize the composition of the IL-2-inducible complexes, EMSAs were performed with three probes corresponding to human GASd/EBSd, FcgRI GAS and mouse site I (Table 1). In contrast to previous reports (John et al, 1999;Meyer et al, 1997), the three probes revealed both complexes in human T cell nuclear extracts, evidencing that they were not a singularity of the human GASd/EBSd element ( Figure 1b). Supershift and inhibition of binding assays were performed with speci®c antisera.…”

“…Two recent studies have underscored the requirement for Stat5 tetramerization mediated by the two PRRIII GAS motifs for e cient promoter recruitment and transcriptional activation (John et al, 1999;Meyer et al, 1997). Although the experiments presented here were not designed to address the respective role of the two GAS elements present within human PRRIII, some of our results di er signi®cantly from those recently reported.…”

“…To analyse this putative synergy and to avoid the complex interactions observed within the native IL-2rE (John et al, 1996(John et al, , 1999Meyer et al, 1997), wild-type and mutant GASd/EBSd trimers were inserted upstream of HSV TK minimal promoter ( Figure 4a). The design of these arti®cial targets was validated by the binding properties of WT and mutants GASd/EBSd motifs ( Figure 1a).…”

The role of Stat5a and Stat5b in signaling by IL-2 family cytokines

“…IL-2 regulates the expression of some of these genes mainly at the transcriptional level, in part through Stat5. So far, one of the best understood examples of transcriptional regulation by IL-2 through Stat5 proteins is from analysis of the IL-2Ra promoter 1999;Lecine et al, 1996;Meyer et al, 1997;Serdobova et al, 1997;Sperisen et al, 1995). As illustrated in Figure 5, the human IL-2Ra promoter contains three well-characterized positive regulatory regions (PRRs).…”

“…PRRII spans the region between 7137 to 764 and binds to an Ets family protein, Elf-1, and the high mobility group proteins, HMG-I/Y Lecine et al, 1996). PRRIII is located between 73780 and 73703 and binds to Stat5, Elf-1, as well as a GATA-1-like protein Meyer et al, 1997;Serdobova et al, 1997). These three positive regulatory regions are conserved in both the human and murine IL-2Ra promoters, except that the binding site for SRF is not conserved in the murine IL-2Ra promoter region.…”