The nuclear protein factors which stimulate synthesis of mRNA of interleukin-2 (IL-2) in the system of surviving murine T lymphocytes are isolated from cells of the spleen and brain of immunized rats. The active fractions of spleen and brain (13-19 and 25 kD, respectively), which interact with the promoter-enhancer sequences of the IL-2 gene localized in the region from +39 to -141 base pairs, are isolated by the method of high performance liquid chromatography from the total nuclear extract. The induction of luciferase synthesis is shown for protein factor-treated Jurkat cells transformed with p-IL-2LUC recombinant plasmid. Key Words: interleukin-2 gene; protein factors; regulationRegulation of the expression of individual genes with transacting factors is an issue at the forefront of molecular biology. This problem involves both an understanding of the nature of these factors and identification of the regulatory sequences of DNA, which are the binding sites of the factors per se. Another aspect concems the mechanisms of competition between transacting proteins and histones for DNA binding sites, which cause a rearrangement of the nucleosomal structure of chromatin of the controlled gene and activation of its transcription [2]. A typical example of an inducible gene is the interleukin-2 (IL-2) gene. It is well known that expression of this lymphokine is a crucial factor in the functions of the immune system and affecting its expression have been identified [6]. However, the factors themselves have not been studied in depth, and little is known about their total amount, hierarchy, and universality. In our previous study [3] protein factors which differ considerably from earlier known factors with respect to molecular weight were isolated from cell nuclei of the spleen and brain of immunized rats. These nuclear proteins form stable specific complexes with the regulatory sequences of the IL-2 gene and stimulate the production of an IL-2-like factor in the system of surviving murine splenic lymphocytes.In the present study we further analyzed the effect of protein factors on the production of IL-2 mRNA in the model system and on the expression of the luciferase (LUC) marker gene under the promoter of the IL-2 gene in order to verify the presence of regulatory proteins common to the nervous and immune systems which act at the gene level. In this study we also identified the region of the

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The ability of the antitumor analogs of luliberin (LH-RH), a hypothalamic peptide hormone, to stimulate the immune function of T cells is examined in experiments with the gone coding for interleukin-2 (IL-2). Recombinant MIL2C or 4xPu DNA containing the marker gene of chloramphenicol acetyltransferase (CAT) under the control of a 2.2 kb promoter of murine IL-2 gene or four copies of purine-rich element (from -292 to -246 base pairs), respectively, is injected in Xenopus laevis oocytes. The promoter activity is blocked by inoculation of the protein fraction of nuclear extracts from resting mouse splenic T cells. The IL-2 gene promoter is dereppressed after injection of the short LH-RH analog L1 (7 amino acid residues) into the oocyte nucleus or cytoplasm. The addition of L1 or L2 (an LH-RH analog consisting of 10 amino acid residues) to the incubation medium activates mouse splenic T ceils and stimulates the synthesis of IL-2 mRNA 2-to 3-fold more intensely than ConA+rlL-2, judging from dot-blot and in situ hybridization data. Cytological analysis of cell culture shows that the presence of L1 and L2 peptides in the culture medium promotes differentiation of T cells. It is hypothesized that the antitumor activity of these peptides is associated with the stimulation of IL-2 synthesis. Key Words: luliberin; interleukin-2 gene; mRNA synthesisIt was hypothesized that protein molecules have biologically active sites responsible for binding to cell receptors, protein-protein recognition, and formation of complexes activating gene expression [4]. The gene coding for interleukin-2 (IL-2) is a convenient tool for the investigation of the role of peptides in the regulation of the expression of eukaryotic genes. Protein product of IL-2 gene plays the key role in the immune response of T cells.The aim of this study was to evaluate the ability of two analogs of the peptide hormone luliberin (LH-RH) to regulate the expression of IL-2 gene.Institute of Experimental Medicine, Russian Academy of Medical Sciences; "Institute of High Molecular Compounds, Russian Academy -of Sciences, St. Petersburg; "'St. Petersburg State University These analogs are peptides consisting of seven (L1) and ten (L2) amino acid residues. The choice of luliberin is based on the fact that it is synthesized not only in hypothalamus, but also in T cells [3]. Tests for antitumor activity showed that L1 and L2 peptides inhibit tumor growth by 40 and 80%, respectively.Previously, we showed that L1 specifically interacts in vitro with the promoter of bovine IL-2 gene and stimulates the production of IL-2-1ike growth factor in a culture of surviving mouse splenic T cells (lymphoblastic transformation data) [2]. The ability of L2 to interact with the promoter of human IL-2 gene was demonstrated by binding to the promoter of digoxin-labeled tL-2 DNA on a nitrocellulose membrane [ 1 ].

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