Enhanced expression of the eosinophil-derived neurotoxin ribonuclease (RNS2) gene requires interaction between the promoter and intron

A novel prognostic predictor of immune microenvironment and therapeutic response in clear cell renal cell carcinoma based on angiogenesis-immune-related gene signature

Background

Clear cell renal cell carcinoma (ccRCC), the most common type of RCC, typically produces no symptoms initially. Patients with ccRCC are at increased risk of developing advanced metastatic disease due to the absence of dependable and effective prognostic biomarkers. Therefore, it is particularly urgent to find optimal stratification of patients with ccRCC to distinguish the clinical benefits of different malignant degrees. Angiogenesis has a profound impact on the malignant behavior of renal cancer cells, and anti-angiogenic drugs have been applied to metastatic renal cancer patients. Moreover, immune function dysregulation is also a significant factor in tumorigenesis. We aim to construct a predictive model that combines angiogenesis and immune-related genes (AIRGs) to aid clinicians in predicting ccRCC prognosis.

Methods

We gathered transcriptome and clinicopathology data from two datasets, the E-MTAB-1980 dataset and the Cancer Genome Atlas (TCGA). We utilized consensus clustering to find new molecular subgroups. A predictive model for the prognosis of angiogenesis-immune-associated genes (AIRGs) was conducted by the lasso and multivariate Cox regression analysis. The signature's predictive ability was then tested in different datasets. Meticulous scrutiny and comprehensive assessment were undertaken, both internally and externally, to establish the prognostic model. Analyses of immunogenomics were carried out to examine the relationship between risk scores and clinical/immune features, including immune cell infiltration, genomic alterations, and response to targeted and immunotherapy therapy.

Results

Our prognostic signature, comprising 4 AIRGs, stood as an independent prognostic factor for ccRCC, while risk scores emerged as a novel indicator for forecasting overall survival. Risk scores exhibited significant associations with various immunophenotypic factors, such as oncogenic pathways, antitumor response, different immune cell infiltration, antitumor immunity, and response to targeted and immunotherapy therapy.

Conclusions

AIRGs-based prognostic prediction model could effectively predict immunotherapy responses and survival outcomes of ccRCC.

Eosinophil development, regulation of eosinophil-specific genes, and role of eosinophils in the pathogenesis of asthma

Eosinophils arise from hematopoietic CD34⁺ stem cells in the bone marrow. They acquire IL-5Rα on their surface at a very early stage during eosinophilopoiesis, and differentiate under the strong influence of interleukin (IL)-5. They then exit to the bloodstream, and enter the lung upon exposure to airway inflammatory signals, including eotaxins. In inflamed tissues, eosinophils act as key mediators of terminal effector functions and innate immunity and in linking to adaptive immune responses. Transcription factors GATA-1, CCAAT/enhancer-binding protein, and PU.1 play instructive roles in eosinophil specification from multipotent stem cells through a network of cooperative and antagonistic interactions. Not surprisingly, the interplay of these transcription factors is instrumental in forming the regulatory circuit of expression of eosinophil-specific genes, encoding eosinophil major basic protein and neurotoxin, CC chemokine receptor 3 eotaxin receptor, and IL-5 receptor alpha. Interestingly, a common feature is that the critical cis-acting elements for these transcription factors are clustered in exon 1 and intron 1 of these genes rather than their promoters. Elucidation of the mechanism of eosinophil development and activation may lead to selective elimination of eosinophils in animals and human subjects. Furthermore, availability of a range of genetically modified mice lacking or overproducing eosinophil-specific genes will facilitate evaluation of the roles of eosinophils in the pathogenesis of asthma. This review summarizes eosinophil biology, focusing on development and regulation of eosinophil-specific genes, with a heavy emphasis on the causative link between eosinophils and pathological development of asthma using genetically modified mice as models of asthma.

GATA transcription factors regulate the expression of the human eosinophil-derived neurotoxin (RNase 2) gene

The transcription factors GATA-1 and GATA-2 have been implicated in promoting differentiation of eosinophilic leukocytes. In this study, we examined the roles of GATA-1 and GATA-2 in activating transcription of the secretory ribonuclease, the eosinophil-derived neurotoxin (EDN/RNase 2). Augmented expression of both GATA-1 and GATA-2 was detected in eosinophil promyelocyte HL-60 clone 15 cells in response to biochemical differentiation with butyric acid. Deletion or mutation of one or both of the two consensus GATA-binding sites in the extended 1000-bp 5' promoter of the EDN gene resulted in profound reduction in reporter gene activity. Antibody-augmented electrophoretic mobility shift and chromatin immunoprecipitation analyses indicate that GATA-1 and GATA-2 proteins bind to both functional GATA consensus sequences in the EDN promoter. Interestingly, RNA silencing of GATA-1 alone had no impact on EDN expression; silencing of GATA-2 resulted in diminished expression of EDN, and also diminished expression of GATA-1 in both butyric acid-induced HL-60 clone 15 cells and in differentiating human eosinophils derived from CD34(+) hematopoietic progenitors. Likewise, overexpression of GATA-2 in uninduced HL-60 clone 15 cells resulted in augmented transcription of both EDN and GATA-1. Taken together, our data suggest that GATA-2 functions directly via interactions with the EDN promoter and also indirectly, via its ability to regulate the expression of GATA-1 in differentiating eosinophils and eosinophil cell lines.

Transcriptional regulation of human eosinophil RNases by an evolutionary- conserved sequence motif in primate genome

Background

Human eosinophil-derived neurotoxin (edn) and eosinophil cationic protein (ecp) are members of a subfamily of primate ribonuclease (rnase) genes. Although they are generated by gene duplication event, distinct edn and ecp expression profile in various tissues have been reported.

Results

In this study, we obtained the upstream promoter sequences of several representative primate eosinophil rnases. Bioinformatic analysis revealed the presence of a shared 34-nucleotide (nt) sequence stretch located at -81 to -48 in all edn promoters and macaque ecp promoter. Such a unique sequence motif constituted a region essential for transactivation of human edn in hepatocellular carcinoma cells. Gel electrophoretic mobility shift assay, transient transfection and scanning mutagenesis experiments allowed us to identify binding sites for two transcription factors, Myc-associated zinc finger protein (MAZ) and SV-40 protein-1 (Sp1), within the 34-nt segment. Subsequent in vitro and in vivo binding assays demonstrated a direct molecular interaction between this 34-nt region and MAZ and Sp1. Interestingly, overexpression of MAZ and Sp1 respectively repressed and enhanced edn promoter activity. The regulatory transactivation motif was mapped to the evolutionarily conserved -74/-65 region of the edn promoter, which was guanidine-rich and critical for recognition by both transcription factors.

Conclusion

Our results provide the first direct evidence that MAZ and Sp1 play important roles on the transcriptional activation of the human edn promoter through specific binding to a 34-nt segment present in representative primate eosinophil rnase promoters.

Isolation, characterization, and evolutionary divergence of mouse RNase 6: evidence for unusual evolution in rodents

The evolution of the ribonuclease A (RNase A) vertebrate-specific enzyme family is interesting in that specific gene lineages appear to be responding to unique selective pressures in wildly diverse manners to generate proteins that are capable of reducing the infectivity of viruses, killing systemic pathogens, and inducing the growth of blood vessels all while maintaining the signature motifs of a ribonuclease. In this paper, we present the DNA sequence and gene structure of Mus musculus RNase 6 and examine the expression pattern and enzymatic activity of the recombinant protein. M. musculus RNase 6 has a limited expression pattern compared to human RNase 6 and is an efficient ribonuclease, with a catalytic efficiency 17-fold higher than that of human protein. Evolutionary analysis reveals that RNase 6 was subject to unusual evolutionary forces (dN/dS = 1.2) in an ancestral rodent lineage before the separation of Mus and Rattus. However, more recent evolution of rodent RNase 6 has been relatively conserved, with an average dN/dS of 0.66. These data suggest that the ancestral rodent RNase 6 was subject to accelerated evolution, resulting in the conserved modern gene, which most likely plays an important role in mouse physiology.

The mouse RNase 4 and RNase 5/ang 1 locus utilizes dual promoters for tissue-specific expression

The ribonuclease A (RNase A) superfamily has been the subject of extensive studies in the areas of protein evolution, structure and biochemistry and are exciting molecules in that they appear to be responding to unique selection pressures, generating proteins capable of multiple and diverse activities. The RNase 4 and RNase 5/ang 1 shared locus breaks a pattern that is otherwise canonical among the members of the RNase A gene superfamily. Conserved among humans, mice and rats, the locus includes two non-coding exons followed by two distinct exons encoding RNase 4 and RNase 5/ang 1. Transcription from this locus is controlled by differential splicing and tissue-specific expression from promoters located 5′ to each of the non-coding exons. Promoter 1, 5′ to exon I, is universally active, while Promoter 2, 5′ to exon II, is active only in hepatic cells in promoter assays in vitro. Transcription from Promoter 2 is dependent on an intact HNF-1 consensus binding site which binds the transcription factor HNF-1α. In summary, RNase 4 and RNase 5/ang 1 are unique among the RNase A ribonuclease genes in that they maintain a complex gene locus that is conserved across species with transcription initiated from tissue-specific dual promoters followed by differential exon splicing.

Multiple roles of antimicrobial defensins, cathelicidins, and eosinophil-derived neurotoxin in host defense

Mammals generate a diverse array of antimicrobial proteins, largely represented by defensins or cathelicidins. The direct in vitro microbicidal activity of antimicrobial proteins has long been considered an important innate immune defense, although the in vivo relevance has only very recently been established for certain defensins and cathelicidins. Mammalian defensins and cathelicidins have also been shown to have multiple receptor-mediated effects on immune cells. Beta-defensins interact with CCR6; murine beta-defensin-2 in addition activates TLR4. Cathelicidins act on FPRL1-expressing cells. Furthermore, several defensins have considerable immunoenhancing activity. Thus, it appears that mammalian antimicrobial proteins contribute to both innate and adaptive antimicrobial immunity.

Identification of a purine-rich intronic enhancer element in the mouse eosinophil-associated ribonuclease 2 (mEar 2) gene

The Mus musculus eosinophil-associated ribonuclease (mEar) gene cluster includes multiple distinct coding sequences that are highly divergent orthologs of the human eosinophil ribonucleases, eosinophil-derived neurotoxin (EDN/RNase 2) and eosinophil cationic protein (ECP/RNase 3). We present a transcriptional analysis of the gene encoding mEar 2, the only member of this cluster with a well-defined expression profile. In this work, we demonstrate that the presence of non-coding exon 1 and the intron in tandem with a 361-bp 5' promoter of mEar 2 results in enhanced reporter gene expression, as much as 6-to 10-fold over the activity observed with the 5' promoter alone. We have identified a conserved purine-rich element in the intron of the mEar 2 gene that is necessary for maximum transcription and that interacts specifically with NFAT-binding proteins in nuclear extracts derived from the mouse LA4 epithelial cell line. Similar intronic enhancers have been described as regulating transcription of the human EDN gene, suggesting an overall conservation of an important regulatory strategy.

Functional characterization of a peroxisome proliferator response-element located in the intron 3 of rat peroxisomal thiolase B gene

Expression of the rat peroxisomal 3-ketoacyl-CoA thiolase gene B is induced by peroxisome proliferators. Although a sequence element like a peroxisome proliferator-activated receptor (PPAR)-binding site is located in the promoter region of this gene, we previously found that this element is competent for the activation by hepatocyte nuclear factor-4, but not functional with PPARalpha. We describe here a new peroxisome proliferator-response element located in the intron 3 (+1422/+1434) that binds in vitro the PPARalpha/retinoid X receptor alpha heterodimer and confers the induction by PPARalpha in transfection assays. We propose a model of regulation of the rat thiolase B gene involving those elements in the promoter and intron 3.

Variations in eosinophil chemokine responses: an investigation of CCR1 and CCR3 function, expression in atopy, and identification of a functional CCR1 promoter

We previously showed in a small group of donors that eosinophils from a subgroup of individuals responded equipotently to CC chemokine ligand (CCL)11/eotaxin and CCL3/macrophage-inflammatory protein-1alpha in assays of eosinophil shape change (CCL3/macrophage-inflammatory protein-1alpha-highly responsive (MHR) donors). In this study, we investigated the functional role of CCL3 in eosinophil responses in 73 donors. MHR donors, identified by their eosinophil shape change responses, represented approximately 19% of the donor pool. Eosinophils from these donors showed increased eosinophil CCR1 expression and also underwent CCL3-mediated chemotaxis and up-regulation of CD11b. All MHR donors gave a history of atopy-associated diseases. In a further study, we prospectively recruited 110 subjects, subdivided into nonatopics or atopics, and investigated expression of CCR1 and CCR3 on eosinophils, basophils, monocytes, and neutrophils. Eosinophil CCR1 expression was non-normally distributed in atopics, although higher CCR1 expression levels were not predictive of a diagnosis of atopy or atopic disease. We identified the CCR1 promoter and investigated its function. We found a minimal promoter within 177 bp of the transcription start site, and an upstream enhancer region that facilitated expression in leukocyte cell lines. Collectively, these data demonstrate that MHR individuals form an important subgroup that, when associated with a diagnosis of allergic disease, may require tailored therapy to modulate eosinophil recruitment. Identification of a functional CCR1 promoter will facilitate the study of possible genetic determinants underlying this potentially important clinical phenotype.

Regulation of ribonuclease expression by estradiol in Rana catesbeiana (Bullfrog)

Multiple ribonucleases are widely found in living organisms, but the function and regulation of individual ribonucleases are still not clear. In the present study, we found that one oocytic ribonuclease, RC-RNase, is developmentally expressed in the liver and stored in the oocyte of the bullfrog, while another ribonuclease, RC-RNase L1, is constitutively expressed and retained in the liver at all stages. In females, the expression of RC-RNase increased with the degree of maturity and the concentration of plasma estradiol during oogenesis. In males, the RC-RNase gene was activated in the liver and the newly synthesized protein was secreted into plasma if estradiol was administered. To investigate the mechanism of estrogen-mediated activation of ribonuclease expression, we cloned the RC-RNase promoter and analyzed the putative transcription factor binding sites, e.g. TATA box, ERE, AP1 and CAAT box. Using luciferase as a reporter gene, we found that an estrogen response element in the promoter of RC-RNase was essential for both basic transcription and estradiol-mediated gene activation in estrogen receptor-positive MCF7 cells. These results support the hypothesis that RC-RNase is synthesized in the liver upon stimulation by estradiol during oogenesis, then secreted into the bloodstream and stored in oocytes for embryonic development.

Sequence variation at two eosinophil-associated ribonuclease loci in humans

Host defense against invading pathogens is of great importance to the survival of higher organisms. We have been studying the evolution of mammalian eosinophil-associated ribonucleases (EARs), which are members of the ribonuclease A superfamily with known antipathogen activities. Earlier studies showed that positive selection promoted rapid diversification of paralogous EAR genes in both primates and rodents. Intraspecifically, however, it is unknown whether these genes also have divergent alleles. The recent discovery that the gene repertoire of the EAR family is much larger in rodents than in primates has led us to consider the possibility that primates maintain a large number of polymorphic alleles to compensate for a smaller gene repertoire. Here we present sequences of 2417 nucleotides at the two EAR loci, the eosinophil-derived neurotoxin (EDN, RNase 2) and eosinophil cationic protein (ECP, RNase 3), from >50 human individuals. Our data demonstrate that the nucleotide diversities (0.06-0.11%) at these loci are typical for human nuclear genes, thus permitting us to reject this polymorphism hypothesis. No significant departure from neutrality is noted and no signs of overdominant selection are observed. Similar patterns were observed in a preliminary study of chimpanzees. In summary, our results suggest that the antipathogen functions of the primate EARs are conserved after they are established and that these proteins are not currently undergoing rapid diversification in response to challenge from invading microorganisms.

Mechanisms of Transcription in Eosinophils: GATA-1, but not GATA-2, Transactivates the Promoter of the Eosinophil Granule Major Basic Protein Gene

Granule major basic protein (MBP) is expressed exclusively in eosinophils, basophils, and placental trophoblasts. To identify thecis-elements and transcription factors involved in regulating MBP expression, we subcloned 3.2 kb of sequence upstream of the exon 9 transcriptional start site (P2 promoter) and serial 5′ deletions into the pXP2 luciferase reporter vector. An 80% decrement in promoter activity was obtained when MBP sequences between bp −117 to −67 were deleted. To identify transcription factors that bind to and transactivate through the bp −117 to −67 region, we first compared the upstream genomic sequences of human and murine MBP; a potential GATA binding consensus site was conserved in the 50-bp region between the two genes. To determine which GATA proteins bind this consensus site, we performed electrophoretic mobility shift assays (EMSAs), which showed that both GATA-1 and GATA-2 can bind to this consensus site. To determine the functionality of this site, we tested whether GATA-1 and GATA-2, either individually or in combination, can transactivate the MBP promoter in the Jurkat T cell line. Cotransfection with a GATA-1 expression vector produced 20-fold augmentation of MBP promoter activity, whereas GATA-2 had no activity. In contrast, combined cotransfection of GATA-1 and GATA-2 decreased the ability of GATA-1 to transactivate the MBP promoter by approximately 50%. Our results provide the first evidence for a GATA-1 target gene in eosinophils, a negative regulatory role for GATA-2 in MBP expression, and possibly eosinophil gene transcription in general during myelopoiesis.

Mechanisms of Transcription in Eosinophils: GATA-1, but not GATA-2, Transactivates the Promoter of the Eosinophil Granule Major Basic Protein Gene

Granule major basic protein (MBP) is expressed exclusively in eosinophils, basophils, and placental trophoblasts. To identify thecis-elements and transcription factors involved in regulating MBP expression, we subcloned 3.2 kb of sequence upstream of the exon 9 transcriptional start site (P2 promoter) and serial 5′ deletions into the pXP2 luciferase reporter vector. An 80% decrement in promoter activity was obtained when MBP sequences between bp −117 to −67 were deleted. To identify transcription factors that bind to and transactivate through the bp −117 to −67 region, we first compared the upstream genomic sequences of human and murine MBP; a potential GATA binding consensus site was conserved in the 50-bp region between the two genes. To determine which GATA proteins bind this consensus site, we performed electrophoretic mobility shift assays (EMSAs), which showed that both GATA-1 and GATA-2 can bind to this consensus site. To determine the functionality of this site, we tested whether GATA-1 and GATA-2, either individually or in combination, can transactivate the MBP promoter in the Jurkat T cell line. Cotransfection with a GATA-1 expression vector produced 20-fold augmentation of MBP promoter activity, whereas GATA-2 had no activity. In contrast, combined cotransfection of GATA-1 and GATA-2 decreased the ability of GATA-1 to transactivate the MBP promoter by approximately 50%. Our results provide the first evidence for a GATA-1 target gene in eosinophils, a negative regulatory role for GATA-2 in MBP expression, and possibly eosinophil gene transcription in general during myelopoiesis.

The Role of Transcription Factor PU.I in the Activity of the Intronic Enhancer of the Eosinophil-Derived Neurotoxin (RNS2) Gene

Eosinophil-derived neurotoxin (EDN) found in the granules of human eosinophils is a cationic ribonuclease toxin. Expression of the EDN gene (RNS2) in eosinophils is dependent on proximal promoter sequences in combination with an enhancer located in the first intron. We further define here the active region of the intron using transfections in differentiated eosinophilic HL60 cells. We show that a region containing a tandem PU.I binding site is important for intronic enhancer activity. This region binds multiple forms of transcription factor PU.I as judged by gel-shift analysis and DNA affinity precipitation. Importantly, introducing point mutations in the PU.I site drastically reduces the intronic enhancer activity, showing the importance of PU.I for expression of EDN in cells of the eosinophilic lineage.

The Role of Transcription Factor PU.I in the Activity of the Intronic Enhancer of the Eosinophil-Derived Neurotoxin (RNS2) Gene

Eosinophil-derived neurotoxin (EDN) found in the granules of human eosinophils is a cationic ribonuclease toxin. Expression of the EDN gene (RNS2) in eosinophils is dependent on proximal promoter sequences in combination with an enhancer located in the first intron. We further define here the active region of the intron using transfections in differentiated eosinophilic HL60 cells. We show that a region containing a tandem PU.I binding site is important for intronic enhancer activity. This region binds multiple forms of transcription factor PU.I as judged by gel-shift analysis and DNA affinity precipitation. Importantly, introducing point mutations in the PU.I site drastically reduces the intronic enhancer activity, showing the importance of PU.I for expression of EDN in cells of the eosinophilic lineage.

Suspensor-derived polyembryony caused by altered expression of valyl-tRNA synthetase in the twn2 mutant of Arabidopsis

The twn2 mutant of Arabidopsis exhibits a defect in early embryogenesis where, following one or two divisions of the zygote, the decendents of the apical cell arrest. The basal cells that normally give rise to the suspensor proliferate abnormally, giving rise to multiple embryos. A high proportion of the seeds fail to develop viable embryos, and those that do, contain a high proportion of partially or completely duplicated embryos. The adult plants are smaller and less vigorous than the wild type and have a severely stunted root. The twn2-1 mutation, which is the only known allele, was caused by a T-DNA insertion in the 5' untranslated region of a putative valyl-tRNA synthetase gene, valRS. The insertion causes reduced transcription of the valRS gene in reproductive tissues and developing seeds but increased expression in leaves. Analysis of transcript initiation sites and the expression of promoter-reporter fusions in transgenic plants indicated that enhancer elements inside the first two introns interact with the border of the T-DNA to cause the altered pattern of expression of the valRS gene in the twn2 mutant. The phenotypic consequences of this unique mutation are interpreted in the context of a model, suggested by Vernon and Meinke [Vernon, D. M. & Meinke, D. W. (1994) Dev. Biol. 165, 566-573], in which the apical cell and its decendents normally suppress the embryogenic potential of the basal cell and its decendents during early embryo development.

From housekeeper to microsurgeon: the diagnostic and therapeutic potential of ribonucleases

The RNA population in cells is controlled post-transcriptionally by ribonucleases (RNases) of varying specificity. Angiogenin, neurotoxins, and plant allergens are among many proteins with RNase activity or significant homology to known RNases. RNase activity in serum and cell extracts is elevated in a variety of cancers and infectious diseases. RNases are regulated by specific activators and inhibitors, including interferons. Many of these regulatory molecules are useful lead compounds for the design of drugs to control tumor angiogenesis, allergic reactions, and viral replication. One RNase (Onconase) and several RNase activators are now in clinical trials for cancer treatment or inhibition of chronic virus infections. Several others, alone or conjugated with specific cell binding molecules, are being developed for their antifungal, antiviral, and antitumor cell activity.

Characterization of the bovine prion protein gene: the expression requires interaction between the promoter and intron

We cloned the part of the bovine PrP gene which contains the 5'-flanking region, exon 1, exon 2 and intron 1 to analyze its promoter region. The 5' non-coding region of the bovine PrP gene consisted of three exons and two introns, and its organization was similar to that of the mouse, rat and sheep PrP genes. The 5'-flanking region of the bovine PrP gene from the transcription start site to nucleotide position -88 was (G + C)-rich (78%) and contained three potential binding sites for the transcription factor Sp1, but no CCAAT-box or TATA-box. This region showed high homology (89%) with that of the sheep PrP gene, but relatively low homology (approximately 46-62%) with the same region of the mouse, rat, hamster and human PrP genes. The position from -88 to -30 within the 5'-flanking region of the bovine PrP gene showed major promoter activity. However, this region was able to function properly only in collaboration with the region at +123 to +891 of intron 1 of the bovine PrP gene.

Intronic enhancer activity of the eosinophil-derived neurotoxin (RNS2) and eosinophil cationic protein (RNS3) genes is mediated by an NFAT-1 consensus binding sequence

The eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are both small, cationic ribonuclease toxins that are stored in and secreted by activated human eosinophilic leukocytes. We have previously shown that optimal expression of the EDN gene is dependent on an interaction between an intronic enhancer element or elements and the 5' promoter region. Here we present evidence demonstrating that the gene encoding ECP is regulated in an analogous fashion and that an intronic enhancer element functioning in both genes is a consensus binding sequence for the transcription factor NFAT-1. Our initial results demonstrate that one or more nuclear proteins isolated from human promyelocytic leukemia (HL-60) cells bind specifically at this consensus site (5'-GGAGAA-3') within the intron of the EDN gene and that disruption of this sequence reduced the characteristic 20-30-fold increase in reporter gene activity observed with the tandem EDN promoter/exon 1/intron construct to background levels. The NFAT-1 consensus site in the ECP gene differs from that found in the EDN gene by a single nucleotide (5'-GGAGAG-3'); the conversion of the 3' G to an A resulted in a further enhancement of the reporter gene activity supported by the ECP promoter/exon 1/intron construct. Interestingly, no "supershift" was observed in gel shift assays performed in the presence of anti-NFAT-1 antiserum, suggesting that a nuclear protein other than NFAT-1 may be acting at this consensus site.