Silencing and trans-activation of the mouse IL-2 gene in Xenopus oocytes by proteins from resting and mitogen-induced primary T-lymphocytes.
The Xenopus oocyte system was used to test functionally, putative trans-active elements involved in the transcriptional control of the mouse interleukin-2 (IL-2) gene in resting and mitogen-induced primary T-lymphocytes. The IL-2 gene injected into the oocyte is active over a wide range of DNA concentrations. This basal activity is silenced by the addition of protein extracts from G0-arrested spleen cells. Extracts from 8 h-stimulated spleen cells do not silence but moderately increase transcription over basal level. When IL-2 transcription is silenced first by an injection of extract from resting spleen cells, the addition of proteins from stimulated cells results in a strong increase in transcription (derepression). Use of proteins from purified splenic T-lymphocytes shows that both silencer(s) and activator(s) are contributed by these cells. Extracts from control tissues have neither a silencing nor stimulatory effect. None of the proteins tested affects the activities of co-injected control genes. Injections with IL-2 promoter mutants indicate that the main target sequence of the silencing and activating factors is a purine region (Pu-box) lying between positions -261 and -292 upstream of the IL-2 gene. Bandshift assays show differential binding of the Pu-box with proteins from resting or activated T-cells.
Mouzaki
A
A
Department of Molecular Biology, University of Geneva, Switzerland.
Weil
R
R
Muster
L
L
Rungger
D
D
D000818:Animals; D001665:Binding Sites; D005786:Gene Expression Regulation; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D009687:Nuclear Proteins / Q000494:pharmacology; D009865:Oocytes; D011401:Promoter Regions, Genetic; D013601:T-Lymphocytes / Q000502:physiology*; D014158:Transcription, Genetic; D014982:Xenopus laevis
D007376:Interleukin-2; D009687:Nuclear Proteins