Ubiquitous and lymphocyte-specific factors are involved in the induction of the mouse interleukin 2 gene in T lymphocytes.

Abstract

The immediate upstream region of the mouse interleukin 2 (Il‐2) gene harbors a strong transcriptional enhancer. This enhancer contains most, if not all of the sequence elements necessary for the T cell specific induction of the Il‐2 gene by the phorbol ester TPA and the plant lectin Concanavalin A. DNase I footprinting studies with fractionated extracts obtained from induced and uninduced E14 T cells revealed numerous recognition sites for potential trans‐acting factors. Five of these sites are also recognized by the TPA‐activated HeLa cell factors AP‐1 and AP‐3. Other sites including two TATA‐boxes, two purine‐rich sequence motifs and two copies of the GGGPuTTTCAA motif are recognized by lymphocyte specific factors. The latter motif is highly conserved between several lymphokine genes and is therefore designated as a T cell element (TCE). In E14 T cells, pentamers of the distal TCEd confer an activity similar to that of the entire Il‐2 enhancer, whereas in B and HeLa cells, the TCEd‐pentamer is inactive as is the Il‐2 enhancer. These data indicate the involvement of the TCEd and its recognition factor(s) in the cell type specific induction of the Il‐2 gene during T cell activation.

Redox signalling by transcription factors NF-κB and AP-1 in lymphocytes

“…For instance, the promoter of the IL-2 gene contains DNA-binding sites for at least four distinct factors: NF-KB, AP-I, NF-AT, and Oct factors [28,57). Some of these factors can physically interact among each other when bound to DNA and thereby synergistically promote their DNA-binding and transactivating activity.…”

Hydrogen peroxide as a potent activator of T lymphocyte functions

“…The regulatory DNA sequences controlling activation of the IL-2 gene have been localized within a region of about 300 bp upstream of the transcription start site [31]. At least four putative transactivating factors have been identified to bind the IL-2 gene enhancer, including the ubiquitous transcription factors NF-xB and AP-1 and the T cellspecific factors NF-AT-1 and Oct-l. To identify the H 2 0 2 -responsive site within the IL-2 promoter we tested a series of deletion and substitution mutants directing expression of the CAT enzyme.…”

Internalization of IL-1 is required for IL-2 gene activation in EL4 thymoma cells

“…pILCAT 0 contained the segment from -7 to -2000, pILCAT 1 contained the segment from -7 to -483, and pILCAT 2/1+ contained the segment from -7 to -293. The positive control for transfection was pTkCAT 21A containing the MSV enhancer, the negative control was pBLCAT 2 containing no enhancer (Serfling et al,1989). These constructs were used to transfect the IL-1 responsive cell EL4 5D3 by the DEAE dextran method.…”

“…Northern analysis and the probes used were described by Falk et al (1989). Transfection of EL4 was done by the DEAE dextran method.…”

“…Cat activity was measured 48h after transfection by conventional methods. The construction of the plasmids used for transfection was described by Serfling et al (1989).…”