The murine interleukin 1 beta gene: structure and evolution

Functional Characteristics of the Mouse Il1b Promoter in Various Tissues Before and After Irradiation

Interleukin-1 beta (IL1B) is a key inducer of inflammation and an important factor in the regulation of hematopoietic stem cells and mesenchymal stromal progenitors. Irradiation of mice with ionizing radiation has been shown to induce a lasting increase in IL1B concentration in peripheral blood. One of the possible mechanisms may be demethylation of CpG cytosines in the Il1b promoter, which has not been characterized in detail for the mouse. In this study, the methylation level of CpGs located in a region between -3562 and -208 bp upstream of the start of transcription is studied in muscles, bones, liver, thymus, spleen, bone marrow, lymph nodes, lungs, and brain. The methylation level is compared to Il1b expression. Tissue-specific features of CpG methylation are established. It is demonstrated that the region between -2420 and -2406 bp is likely a part of the mouse Il1b promoter/enhancer and may determine the base level of Il1b expression in various tissues. Irradiation at a dose of 6 Gy does not change the methylation profile of most studied CpGs, and therefore, the cause of the stably increased IL1B level after irradiation is unlikely to be a change in the methylation of the studied CpGs in investigated tissues.

Molecular characterization and expression analysis of the interleukin 1b gene in Pacific cod (Gadus macrocephalus)

Interleukin 1b (IL-1b) is a member of the cytokine family that serves as major mediators for early pro-inflammatory responses. During artificial breeding of Pacific cod (Gadus macrocephalus), outbreaks of NNV in the early development stages could lead to high mortality. Recent research reported that IL-1b participated in the host-virus interaction against NNV infection, however, no IL-1b gene has been identified from Pacific cod so far. In this study, we described the identification and characterization of a IL-1b from Pacific cod transcriptome at both transcript and protein level. Sequence alignment and phylogenetic analysis were conducted to determine and confirm their evolutionary relationship. Expression analysis revealed that IL-1b was expressed in all tested tissues and the western blot analysis confirmed the same expression profiles using purified recombinant IL-1b protein. In addition, significant up-regulation was detected in IL-1b transcripts during early development stages at 30dph and 50dph. After challenged with poly I:C, IL-1b was significantly induced after 24 h. Taken together, these results strongly suggested that IL-1b might play an essential role in innate defense mechanism of Pacific cod.

Induced cumulus expansion of poor quality buffalo cumulus oocyte complexes by Interleukin-1beta improves their developmental ability

The present study was conceived with the aim of modulating the cumulus expansion characteristics of poor quality (BCB-) buffalo oocyte complexes (COCs) in order to improve their fertilization outcomes. BCB- COCs were subjected to in vitro maturation (IVM) in presence of Interleukin-1 beta (IL-1β) along with BCB- (control) and good quality (BCB+) COCs. Results were assessed morphologically, by scanning electron microscopy (SEM) and by expression analysis of cumulus expansion related genes. Also, numbers of zona pellucida bound spermatozoa were counted and development rates of oocytes were monitored under different groups. Expression of versican isoforms and ADAMTS-1 was observed to be significantly different between cumulus cells of BCB+ and BCB- COCs. Upon IL-1β supplementation, ADAMTS-1 expression increased in BCB- COCs along with corresponding cumulus expansion rates. SEM analysis also revealed improved cumulus expansion in IL-1β supplemented BCB- COCs. HAS2 and TNFAIP-6 were significantly up-regulated after IL-1β supplementation while PTGS2 expression remained unaffected. Significantly more numbers of sperms crossed the cumulus barrier, especially in 100 ng/mL IL-1β supplemented COCs. Besides, cleavage and blastocyst development rates were also improved upon IL-1β addition. We concluded that IL-1β supplementation in IVM medium can improve cumulus expansion and development ability of poor quality buffalo oocytes.

Comparative proteomic and regulatory network analyses of the elongating pig conceptus

Embryo loss during peri-implantation can approach 20% in swine following artificial insemination or natural mating and coincides with rapid conceptus elongation. The objective of the present study was to establish a comprehensive profile of the abundant proteins of the pig conceptus at the time prior to implantation and identify stage-specific changes during elongation. The abundant proteins of a homogenous population of gestational day-11 ovoid (0.7-1 cm) and gestational day-12 filamentous (15-20 cm) porcine concepti were compared by extracting proteins from three independent conceptus pools and separating the proteins by 2-DE. Proteins in 305 spots were analyzed by MALDI-TOF or additionally by LC-MS/MS and 275 were positively identified representing 174 distinct proteins. The proteins could be classified into the following functional categories: cell proliferation/differentiation, cytoskeleton, metabolism, and stress response. Based on spot density, 35 proteins associated with cell proliferation, differentiation, apoptosis, and embryo/maternal signaling, were found to be differentially expressed between ovoid and filamentous concepti. A comparison of the protein expression profile with transcriptomic data from pig concepti of the same developmental stages identified similarities and dissimilarities between protein and mRNA expression profiles. This proteomic study helps to elucidate the biological mechanisms underlying the early embryonic development of the pig.

Cloning and expression analysis of three striped trumpeter (Latris lineata) pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-8, in response to infection by the ectoparasitic, Chondracanthus goldsmidi

This study reports the cloning and sequencing of three striped trumpeter (Latris lineata Forster) pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-8, as well as their differential expression in response to an infection by the ectoparasite Chondracanthus goldsmidi. The striped trumpeter TNF-alpha transcript consisted of 1093 bp, including a 759 bp ORF which translated into a 253 aa transmembrane peptide. The sequence contained a TACE cut site, that would produce a 167 aa soluble peptide containing the TNF ligand family signature. The IL-1beta sequence consisted of 963 bp, including a 774 bp ORF which translated into a 258 aa protein. The protein lacked both a signal peptide and an ICE cleavage site, but did contain the IL-1 family signature. The sequence for the chemokine IL-8 contained 906 bp, with an ORF of 297 bp, which translated into a 99 aa protein. The protein lacked an ELR motif as is common with many teleost IL-8 sequences. The differential expression of the three cytokine genes in parasitized fish was investigated via quantitative real-time PCR. A significant up-regulation of all three pro-inflammatory cytokines was found in the gills, which were the site of parasite attachment. Examination of head kidney cells revealed a significant up-regulation of TNF-alpha, but not IL-1beta or IL-8. Conversely, the spleen cells showed significant up-regulation of both IL-1beta and IL-8, but not TNF-alpha. These findings allow for more detailed investigations of the striped trumpeter immune response.

Molecular cloning and expression of a functional anti-inflammatory protein, Sj16, of Schistosoma japonicum

Schistosomes are the causative agent of schistosomiasis. In the infected host, significant inflammatory response to the parasite is not observed. Previous studies of Schistosoma mansoni showed that this subdued inflammatory response was due to a 16-kDa protein, Sm16, which is present in high levels in the secretions of schistosomula. Here we report the cloning and characterization of a gene (named Sj16) from Schistosoma japonicum. Sequence analysis showed that Sj16 shares 99% identity with Sm16 in its nucleotide sequence, and 100% identity in its protein sequence. While previous studies reportedly failed to obtain the soluble recombinant protein of Sm16, we expressed and purified recombinant Sj16 (rSj16) from Escherichia coli. Western blot and ELISA analyses showed that S. japonicum-infected rabbit sera could not recognize rSj16, indicating that native Sj16 may fail to induce circulating antibodies during S. japonicum infection. In vivo, rSj16 dramatically suppressed the recruitment of thioglycollate-mediated leukocytes to the peritoneal cavity of BALB/c mice, accompanied by marked up-regulation of IL-10 and IL-1RA transcripts, and down-regulation of IL-12p35, IL-1 beta and MIP-2 transcripts in peritoneal cells. Further analysis revealed that rSj16 also suppressed thioglycollate-induced peritoneal macrophage maturation. These results demonstrate that rSj16 has an anti-inflammatory function.

Comparison of the human and canine cytokines IL-1(alpha/beta) and TNF-alpha to orthologous other mammalians

The cytokines interleukin-1 (IL-1alpha and IL-1beta) and the tumor necrosis factor-alpha (TNF-alpha) both play a major role in the initiation and regulation of inflammation and immunity responses. Polymorphisms within the gene sequences of these cytokines IL-1 and TNF-alpha have been proposed to play an important role in the pathogenesis of certain diseases. Affecting nearly every organ, various diseases, including some cancers, are described to be associated with an increased level of IL-1 and TNF-alpha proteins, for example, solid tumors, hematologic malignancies, malignant histiocytosis, autoimmune disorders, Alzheimer's disease, Parkinson's disease, sepsis, and rheumatoid arthritis. Regarding genetic backgrounds and pathways, numerous canine diseases show close similarities to their human counterparts. As a genetic model, the dog could be used to unravel the genetic mechanisms, for example, in particular the predispositions, the development, and progression of cancer and metabolic diseases. The identity comparison of gene and protein sequences of different species could be used to elucidate the structure and function of the genes and proteins by identifying the evolutionary conserved regions and domains. Herein we analyzed in detail the mRNA and protein structures and identities of the present known mammalian (human, canine, murine, rat, ovine, equine, feline, porcine, and bovine) TNF-alpha, IL-1alpha, and IL-1beta mRNAs and proteins. Additionally, based on the canine genome sequence, we derived in silico the complete mRNA structures of the IL-1alpha and IL-1beta mRNAs.

The chicken proinflammatory cytokines interleukin-1beta and interleukin-6: differences in gene structure and genetic location compared with their mammalian orthologues

The genes encoding the chicken proinflammatory cytokines interleukin (IL)-1B and IL-6 were cloned, sequenced and mapped. The exon:intron structure of the coding region of chicken IL1B corresponds almost exactly to those of mammalian IL1B. As yet, we have no evidence for a 5'-UTR non-coding exon equivalent to that found in mammalian IL1B. The exon:intron structure of chicken IL6 differs from those of mammalian IL6, having one exon fewer (the first two exons in mammalian IL6 genes appear to be fused in the chicken gene). We were unable to clone or sequence the promoter of chicken IL1B. The chicken IL6 promoter shares a number of potential regulatory sequences similar to those found in the human IL6 promoter. These putative elements include (5'-3') a glucocorticoid response element (GRE), an AP-1 binding site, an NF-IL-6 binding site (albeit in the reverse orientation), an NF-kappaB binding site, a second AP-1 binding site and a TATAAA box. A further GRE, a cAMP response element and regions with homology to c-fos serum responsive elements or retinoblastoma control elements were absent. Promoter sequence polymorphisms were not identified in eight different inbred chicken lines. A restriction single-stranded conformational polymorphism was identified which enabled chicken IL1B to be genetically mapped to one end of chromosome 2. Chicken IL6 was mapped by fluorescent in situ hybridization also to chromosome 2, at an FLpter of 0.26.

Evolution of interleukin-1beta

All jawed vertebrates possess a complex immune system, which is capable of anticipatory and innate immune responses. Jawless vertebrates possess an equally complex immune system but with no evidence of an anticipatory immune response. From these findings it has been speculated that the initiation and regulation of the immune system within vertebrates will be equally complex, although very little has been done to look at the evolution of cytokine genes, despite well-known biological activities within vertebrates. In recent years, cytokines, which have been well characterised within mammals, have begun to be cloned and sequenced within non-mammalian vertebrates, with the number of cytokine sequences available from primitive vertebrates growing rapidly. The identification of cytokines, which are mammalian homologues, will give a better insight into where immune system communicators arose and may also reveal molecules, which are unique to certain organisms. Work has focussed on interleukin-1 (IL-1), a major mediator of inflammation which initiates and/or increases a wide variety of non-structural, function associated genes that are characteristically expressed during inflammation. Other than mammalian IL-1beta sequences there are now full cDNA sequences and genomic organisations available from bird, amphibian, bony fish and cartilaginous fish, with many of these genes having been obtained using an homology cloning approach. This review considers how the IL-1beta gene has changed through vertebrate evolution and whether its role and regulation are conserved within selected non-mammalian vertebrates.

A dual role for the SDF-1/CXCR4 chemokine receptor system in adult brain: isoform-selective regulation of SDF-1 expression modulates CXCR4-dependent neuronal plasticity and cerebral leukocyte recruitment after focal ischemia

The chemoattractant stromal cell-derived factor-1 (SDF-1) and its receptor CXC chemokine receptor 4 (CXCR4) are key modulators of immune function. In the developing brain, SDF-1 is crucial for neuronal guidance; however, cerebral functions of SDF-1/CXCR4 in adulthood are unclear. Here, we examine the cellular expression of SDF-1 isoforms and CXCR4 in the brain of mice receiving systemic lipopolysaccharide (LPS) or permanent focal cerebral ischemia. CXCR4 mRNA was constitutively expressed in cortical and hippocampal neurons and ependymal cells. Hippocampal neurons targeted the CXCR4 receptor to their somatodendritic and axonal compartments. In cortex and hippocampus, CXCR4-expressing neurons exhibited an overlapping distribution with neurons expressing SDF-1 transcripts. Although neurons synthesized SDF-1alpha mRNA, the SDF-1beta isoform was selectively expressed by endothelial cells of cerebral microvessels. LPS stimulation dramatically decreased endothelial SDF-1beta mRNA expression throughout the forebrain but did not affect neuronal SDF-1alpha. After focal cerebral ischemia, SDF-1beta expression was selectively increased in endothelial cells of penumbral blood vessels and decreased in endothelial cells of nonlesioned brain areas. In the penumbra, SDF-1beta upregulation was associated with a concomitant infiltration of CXCR4-expressing peripheral blood cells, including macrophages. Neuronal SDF-1alpha was transiently downregulated and neuronal CXCR4 was transiently upregulated in the nonlesioned cerebral cortex in response to ischemia. Although endothelial SDF-1beta may control cerebral infiltration of CXCR4-carrying leukocytes during cerebral ischemia, the neuronal SDF-1alpha/CXCR4 system may contribute to ischemia-induced neuronal plasticity. Thus, the isoform-specific regulation of SDF-1 expression modulates neurotransmission and cerebral infiltration via distinct CXCR4-dependent pathways.

Effects of Helicobacter pylori infection on gastric acid secretion and serum gastrin levels in Mongolian gerbils

BACKGROUND AND AIMS

Body gastritis caused by Helicobacter pylori infection appears to inhibit gastric acid secretion. The aim of this study was to determine the effects of H pylori infection on gastric acid secretion and clarify its mechanisms with reference to interleukin 1beta (IL-1beta).

METHODS

(1) Mongolian gerbils were inoculated orally with H pylori. Before, six, and 12 weeks after inoculation, serum gastrin levels, gastric acid output, and IL-1beta mRNA levels in the gastric mucosa were determined. Pathological changes were also determined according to the updated Sydney system. (2) Effects of recombinant human IL-1 receptor antagonist (rhIL-1ra) on gastric acid output and serum gastrin levels were also determined.

RESULTS

(1) Scores for activity and inflammation of gastritis and serum gastrin levels were significantly increased, and gastric acid output was significantly decreased six and 12 weeks after inoculation with H pylori. IL-1beta mRNA levels in the gastric mucosa were also elevated six and 12 weeks after inoculation with H pylori. (2) Acid output and serum gastrin levels in the infected groups returned to control levels after rhIL-1ra injection.

CONCLUSIONS

Gastric acid secretion is decreased and serum gastrin levels are increased in Mongolian gerbils infected with H pylori. This change in gastric acid secretion appears to be mediated by IL-1beta induced by H pylori infection.

Identification of microsatellite length polymorphism by a polymerase chain reaction-based assay at IL-1beta gene locus in cancer cells

It has long been considered that genetic instability is an integral component of human neoplasia, however the frequency of microsatellite instability in human melanoma and non-melanoma skin cancer was less evidenced. We report here an alteration at the complex dinucleotide repeat (TC)n sequence in the interleukin 1-beta gene locus by polymerase chain reaction (PCR)-based assay in mouse melanoma as well as in various cancer cells, which may provide a simple, rapid, non-radioactive screening assay for cancer detection.

Interleukin-17: A new bone acting cytokine in vitro

Interleukin-17 (IL-17) is a recently cloned cytokine that is exclusively produced by activated T cells, but its receptor has been found on several cells and tissues. Like other proinflammatory cytokines produced by activated T cells, IL-17 may affect osteoclastic resorption and thereby mediate bone destruction accompanying some inflammatory diseases. In the present study, we investigated whether osteogenic cells possess the receptor for IL-17 (IL-17R) and whether IL-17 affects osteoclastic resorption. We found that IL-17R mRNA is expressed both in mouse MC3T3-E1 osteoblastic cells and fetal mouse long bones, suggesting that osteogenic cells may be responsive to IL-17. In fetal mouse long bones, IL-17 had no effect on basal and IL-1beta-stimulated osteoclastic bone resorption, but when given together with tumor necrosis factor-alpha (TNF-alpha) it increased bone resorption dose dependently in serum-free conditions. In addition, IL-17 increased TNF-alpha-induced IL-1alpha, IL-1beta, and IL-6 mRNA expression in fetal mouse metatarsals and IL-1alpha and IL-6 mRNA expression in MC3T3-E1 cells. In conclusion, IL-17R mRNA was expressed by mouse osteoblastic cells and fetal mouse long bones, and IL-17 in combination with TNF-alpha, but not IL-1beta, increased osteoclastic resorption in vitro. IL-17 may therefore affect bone metabolism in pathological conditions characterized by the presence of activated T cells and TNF-alpha production such as rheumatoid arthritis and loosening of bone implants.

Dynamic regulation of the proinflammatory cytokine, interleukin-1beta: molecular biology for non-molecular biologists

Interleukin-1beta (IL-1beta) is a key mediator and modulator of a wide array of physiological responses important for survival. It is created by a variety of cell types, including immune cells, glia, and neurons. It is a very potent biological molecule, acting both at the periphery as well as within the central nervous system. The production and release of IL-1beta is tightly regulated by far more complex processes than previously thought. An appreciation of this complexity is necessary for proper interpretation of apparent contradictions in the literature where different aspects of IL-1beta expression are measured. Given that many researchers are not molecular biologists by training, yet need an appreciation of the controls that regulate the function of key proteins such as IL-1beta, this review is aimed at both: (a) clarifying the multiple levels at which IL-1beta production is modulated and (b) using IL-1beta regulation to explain the dynamics of gene regulation to non-molecular biologists. Three major topics will be discussed. First, regulation of IL-1beta production will be examined at every level from extracellular signals that trigger gene activation through release of active protein into the extracellular fluid. Second, regulation of IL-1beta bioavailability and bioactivity will be discussed. This section examines the fact that even after IL-1beta is released, it may or may not be able to exert a biological action due to multiple modulatory factors. Last is the introduction of the idea that IL-1beta regulation is, at times, beyond the direct control of host; that is, when IL-1beta production becomes dysregulated by pathogens.

Extracellular uridine nucleotides initiate cytokine production by murine dendritic cells

While it is recognized that activated dendritic cells perform their immune functions with greater efficacy, it is not altogether clear what factors are responsible for such activation. Recent evidence points to an important role for extracellular nucleotides in the modulation of leukocyte function. In the present study we investigated the ability of extracellular nucleotides to activate CD11c(+) murine dendritic cells. Mobilization of intracellular calcium was observed following treatment of these cells with UTP or UDP, but not ATP. Furthermore, this nucleotide receptor was pertussis toxin-sensitive, suggesting the presence of a P2Y nucleotide receptor. Such receptors were not present on murine peritoneal macrophages or on CD11c-negative leukocyte populations. Importantly, activation of these P2Y nucleotide receptors on dendritic cells provided a potent stimulus for cytokine mRNA expression and secretion. Thus, expression of a P2Y nucleotide receptor on CD11c(+) dendritic cells functions to mobilize intracellular calcium and to induce cytokine production.

Production of mice deficient in genes for interleukin (IL)-1alpha, IL-1beta, IL-1alpha/beta, and IL-1 receptor antagonist shows that IL-1beta is crucial in turpentine-induced fever development and glucocorticoid secretion

Interleukin (IL)-1 is a major mediator of inflammation and exerts pleiotropic effects on the neuro-immuno-endocrine system. To elucidate pathophysiological roles of IL-1, we have first produced IL-1alpha/beta doubly deficient (KO) mice together with mice deficient in either the IL-1alpha, IL-1beta, or IL-1 receptor antagonist (IL-1ra) genes. These mice were born healthy, and their growth was normal except for IL-1ra KO mice, which showed growth retardation after weaning. Fever development upon injection with turpentine was suppressed in IL-1beta as well as IL-1alpha/beta KO mice, but not in IL-1alpha KO mice, whereas IL-1ra KO mice showed an elevated response. At this time, expression of IL-1beta mRNA in the diencephalon decreased 1.5-fold in IL-1alpha KO mice, whereas expression of IL-1alpha mRNA decreased >30-fold in IL-1beta KO mice, suggesting mutual induction between IL-1alpha and IL-1beta. This mutual induction was also suggested in peritoneal macrophages stimulated with lipopolysaccharide in vitro. In IL-1beta KO mice treated with turpentine, the induction of cyclooxygenase-2 (EC 1.14.99.1) in the diencephalon was suppressed, whereas it was enhanced in IL-1ra KO mice. We also found that glucocorticoid induction 8 h after turpentine treatment was suppressed in IL-1beta but not IL-1alpha KO mice. These observations suggest that IL-1beta but not IL-1alpha is crucial in febrile and neuro-immuno-endocrine responses, and that this is because IL-1alpha expression in the brain is dependent on IL-1beta. The importance of IL-1ra both in normal physiology and under stress is also suggested.

IL-1alpha, IL-1beta, IL-6, and TNF-alpha steady-state mRNA levels analyzed by reverse transcription-competitive PCR in bone marrow of gonadectomized mice

Loss of gonadal function in both females and males is associated with increased rates of bone loss by a yet unidentified mechanism. There is ample evidence that cytokines that are produced in the bone microenvironment and stimulate the activity and/or formation of osteoclasts are involved. In the present study, we examined whether gonadectomy increases cytokine production via increased transcription in the bone marrow of mice. For this, the in vivo steady-state mRNA levels of multiple cytokines were determined in the central bone marrow compartment of mice at different time points following ovariectomy or orchidectomy by reverse transcription-competitive polymerase chain reaction. The limit of detectable differences in mRNA expression was approximately 2-fold. Bone marrow mRNA levels of the cytokines interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) were elevated up to 30-fold after treatment of mice with lipopolysaccharide. Following gonadectomy, there were no differences in the mRNA expression of these cytokines in bone marrow of female and male mice 4, 7, and 14 days after surgery. Gender steroid deficiency does not, therefore, increase steady-state mRNA levels of IL-1alpha, IL-1beta, IL-6, and TNF-alpha in cells of the central bone marrow compartment in mice. If changes have occurred these should have been less than 2-fold or in a small cell population. These results do not preclude an important role of these cytokines in the induction of bone loss after gonadectomy. For example, bone marrow cells situated close to the bone surface or bone cells may be responsible for increased cytokine synthesis. Alternatively, the loss of gender steroids may alter post-transcriptional events in cytokine synthesis and activity or may modify the responsiveness of target cells.

Constitutive activity of the murine IL-1 beta promoter is regulated by a transcriptional repressor

Constitutive expression of IL-1 beta is kept under tight control in healthy tissues. So far no repressor elements down-regulating expression of the IL-1 beta gene have been described. In the current study, a deletion analysis approach was utilized to identify a region spanning -306/-292 bp upstream of the transcription start site, which appeared to down-regulate constitutive IL-1 beta promoter activity. Further deletion analysis confirmed that the -306/-292 bp element possessed repressor activity. A putative NF-kappaB binding site and an AATATT palindromic sequence were identified within the 306/-292 bp element. Notably, no binding of NF-kappaB was observed in gel shift assays, suggesting that another nuclear activity binding to the 14 bp sequence suppressed NF-kappaB binding. Further, the results of gel shift assays demonstrated that the AATATT palindromic sequence, which lies immediately downstream of the putative NF-kappaB site, may be responsible, in conjunction with the NF-kappaB site, for constitutive suppression of the IL-1 beta promoter. Thus, our results suggest that a novel repressor element may play a potentially important role in suppressing constitutive activity of the IL-1 beta promoter.

Analysis of brain mRNA by reverse transcription-polymerase chain reaction and hybridization with digoxigenin-labeled DNA probe

The interleukin-1 family of polypeptides (IL-1 alpha, IL-1 beta and IL-1 receptor antagonist (RA)) induces various centrally mediated host defense responses to infectious pathogens. Considerable interest has focussed on IL-1 as a mediator in disease and in the production of systemic acute phase responses. We have recently studied the effects of a peripheral stimulation by intraperitoneal (i.p.) administration of lipopolysaccharide (LPS) on the mRNAs expressions of IL-1 (alpha, beta, RA) and their receptors (IL-1 receptor type I and type II (IL-1R1, IL-1R2)) in the central nervous system (CNS). The levels of these expressions being very low in the CNS, the reverse transcription-polymerase chain reaction (RT-PCR) techniques are required for these studies. RT-PCR is a developed method of identifying mRNAs in very small amount of nucleic acid. We have previously developed a method to choose specific PCR primers. The detection of specific PCR products is extremely important. Since amplifications with these specific PCR primers can be achieved under the same conditions (buffers and temperatures) reliable results can be obtained. Characterization of a PCR product requires the use of a specific DNA probe that hybridizes to the region of interest. In addition to providing specificity of detection, the use of labeled DNA probes provides increased sensitivity over ethidium bromide staining. We have previously described a method of synthesis of non-radioactive probe labeled with digoxigenin by nested PCR. Moreover the major advantage to the use of non-radioactive label is that it does not have a short half-life and can last for weeks or even months. A quantification of the PCR products can be obtained using a method based on the analysis of photographic negatives of agarose gels.

Studies on the contribution of c-fos/AP-1 to arthritic joint destruction

Features characteristic to rheumatoid joint destruction, including synovial overgrowth and bone resorption, are experimentally produced by augmenting c-fos gene expression. We tested here if arthritic joint destruction was inhibited upon inactivation of the c-fos/AP-1 signal by administering short double-stranded AP-1 DNA oligonucleotides into mice with collagen-induced arthritis to compete for the binding of AP-1 in vivo at the promoter binding site. Arthritic joint destruction was inhibited in a sequence-specific and dose-dependent manner by oligonucleotides containing the AP-1 sequence. The oligonucleotides inhibited gene expression at the transcriptional level. Nucleotide sequences besides AP-1 also appeared to be important structurally for binding of AP-1 onto DNA and for the stability of oligonucleotides against nucleases. Immunohistochemical chase experiment administering biotinylated oligonucleotides into arthritic mice showed that AP-1 oligonucleotides reached the inflamed joint. Thus, activation of c-fos/AP-1 appears essentially important in arthritic joint destruction.

Leukemia inhibitory factor ameliorates experimental anti-GBM Ab glomerulonephritis

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that has been identified in acute and chronic inflammatory conditions such as rheumatoid arthritis, sepsis, and renal allograft rejection. We investigated the glomerular expression of LIF at 30 minutes, and 3, 6, 9, 15 and 24 hours after administration of anti-GBM Ab (N = 3) by the RNase protection assay. Control rats received rabbit sera and were sacrificed at 30 minutes, and 6 and 24 hours. LIF mRNA relative to GAPDH mRNA was detected at low levels within the glomeruli of occasional control rats. However with the induction of anti-GBM Ab GN, there was a marked increase in LIF steady-state mRNA beginning at three hours which persisted through 24 hour. LIF mRNA was also detected in cultured mesangial cells stimulated with IL-1 beta, identifying this cell type as a potential glomerular source for this cytokine. To investigate the in vivo effect of LIF, Lewis rats were continuously infused with recombinant (r) human (h) LIF (approximately 0.5 ng/hr) or saline vehicle i.p. with ALZA osmotic pumps beginning at t = -24 hours (N = 8). All rats were injected with anti-GBM Ab intravenously at t = 0 (N = 16). LIF infusion decreased 24-hour urinary protein excretion by 85% (17 +/- 15 vs. 114 +/- 37 mg/day, P = 0.0001) and was associated with a 60% decrease in glomerular macrophage infiltration (0.8 +/- 0.2 vs. 2.0 +/- 0.6 ED-1 cells/glom, P = 0.0001). The administration of rhLIF did not affect the binding of the anti-GBM Ab to glomeruli. The beneficial effects of LIF were associated with a decrease in glomerular MCP-1 (56%), IL-1 (41%) and TNF (17%) steady state mRNA expression. The latter was associated with a 29% decrease in TNF-alpha protein expression within the glomerular lysate of nephritic rats administered LIF when compared with control rats. These data demonstrate a potential role for LIF in the therapy of anti-GBM Ab GN.

Mice deficient in IL-1beta manifest impaired contact hypersensitivity to trinitrochlorobenzone

Mice rendered deficient in IL-1 beta by gene targeting in embryonic stem cells develop and grow normally in a protected laboratory environment. Endotoxin-stimulated peritoneal macrophages from IL-1beta-deficient mice showed normal synthesis and cellular release of IL-1alpha after treatment with 5 mM ATP demonstrating that IL-1beta is not necessary for expression and release of the IL-1alpha isoform. Mice deficient in IL-1beta showed unaltered sensitivity to endotoxic shock, with or without pretreatment with D-galactosamine. In contrast, IL-1beta-deficient mice showed defective contact hypersensitivity responses to topically applied trinitrochlorobenzene (TNCB). This defect could be overcome either by application of very high doses of sensitizing antigen, or by local intradermal injection of recombinant IL-1beta immediately before antigen application. These data demonstrate an essential role for IL-1beta in contact hypersensitivity and suggest that IL-1beta acts early during the sensitization phase of response. They suggest an important role for IL-1beta in initiation of the host of response at the epidermal barrier.

Identification of dioxin-responsive elements (DREs) in the 5' regions of putative dioxin-inducible genes

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an exogenous ligand for the cytosolic aryl hydrocarbon receptor (AhR), a ligand-inducible transcription factor whose exact physiological role remains elusive. TCDD has been shown to modulate the expression of a large array of genes, albeit often indirectly, by demonstration of protein or mRNA upregulation. Here, by computer analysis of available promoter sequences, we identify dioxin-responsive elements in the promoter regions of many putative AhR regulated and therefore dioxin-inducible genes.

Molecular cloning of equine interleukin-1 alpha and -beta cDNAs

Equine interleukin-1 alpha (IL-1 alpha) and IL-1 beta were molecularly cloned to establish a basis for research on inflammatory and immune responses in the horse. Equine peripheral blood mononuclear cells (PBMC) were stimulated with lipopolysaccharide (LPS), and cDNA clones of equine IL-1 alpha and IL-1 beta covering the whole coding sequences were isolated from them. These equine IL-1 alpha and IL-1 beta clones contained open reading frames encoding 271 and 269 amino acids, respectively. The deduced amino acid sequence of equine IL-1 alpha showed 71.6% and 60.2% similarity with that of human and murine IL-1 alpha, respectively. Similarly, the amino acid sequence of equine IL-1 beta showed 66.7% and 61.8% similarity with that of human and murine IL-1 beta, respectively. In both equine IL-1 alpha and IL-1 beta, amino acids at miristoylation sites were well conserved. Dot blot analysis indicated that the expression of IL-1 beta was predominant to that of IL-1 alpha in equine PBMC stimulated with LPS or phorbol myristate acetate.

Expression of interleukin 1 alpha, interleukin 1 beta and interleukin 1 receptor antagonist mRNA in mouse brain: regulation by bacterial lipopolysaccharide (LPS) treatment

Lipopolysaccharide (LPS) stimulation is known to induce interleukin-1 (IL-1) mRNA expression in various immune cell types. Since IL-1 synthesis has been suggested to occur locally in brain tissue, we investigated the expression of IL-1 (alpha and beta) and IL-1 receptor antagonist (IL-1ra) mRNAs in various structures of the central nervous system, as well as in the spleen, following intraperitoneal injection of LPS (100 micrograms/mouse). After RNA extraction and amplification by the reverse transcription-polymerase chain reaction (RT-PCR), the PCR products were separated on an agarose gel, transferred and hybridized with digoxigenin-labeled probes synthetized by nested PCR. Glyceraldehyde phosphate deshydrogenase mRNA was used as an internal control. Under basal conditions the expression of IL-1 alpha, IL-1 beta and IL-1ra mRNAs in the brain was extremely low for the three cytokines; in the spleen these mRNAs were clearly detectable. Following LPS stimulation, mRNAs were strongly increased in all the tested tissues (cortex, hippocampus, hypothalamus, cerebellum, pituitary and spleen). The kinetics of mRNAs expressions in the brain were similar for all the tested regions, with a maximum at 6 h and a decrease up to 24 h after LPS administration. In the spleen the maximum was observed as soon as 1 h following stimulation. In conclusion, peripheral LPS stimulation induces a strong and transient expression of IL-1 alpha and IL-1 beta mRNAs in the brain. IL-1ra mRNA is also stimulated by LPS in various regions of the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Resistance to fever induction and impaired acute-phase response in interleukin-1 beta-deficient mice

We used gene targeting in embryonic stem cells to introduce an IL-1 beta null allele in mice. The IL-1 beta-deficient mice develop normally and are apparently healthy and fertile. The IL-1 beta null mice responded normally in models of contact and delayed-type hypersensitivity or following bacterial endotoxin LPS-induced inflammation. The IL-1 beta-deficient mice showed equivalent resistance to Listeria monocytogenes compared with wild-type controls. In contrast, when challenged with turpentine, which causes localized inflammation and tissue injury, the IL-1 beta mutant mice exhibited an impaired acute-phase inflammatory response and were completely resistant to fever development and anorexia. These results highlight a central role for IL-1 beta as a pyrogen and a mediator of the acute-phase response in a subset of inflammatory disease models, and support the notion that blocking the action of a single key cytokine can alter the course of specific immune and inflammatory responses.

Evolution of the interleukin-1 gene family in mammals

The phylogeny of interleukin-1 family genes shows that human interleukin-1 alpha (IL-1 alpha) is more closely related to IL-1 alpha of the bovine than to IL-1 alpha of the mouse, whereas human interleukin-1 beta (IL-1 beta) is more closely related to IL-1 beta of the mouse than to IL-1 beta of the bovine. The IL-1 receptor antagonist (IL-1ra) shows homology to the C-terminal region of both IL-1 alpha and IL-1 beta. In the C-terminal region, the IL-1 alpha genes of human and mouse have diverged more from each other at nonsynonymous sites than have either IL-1 beta or IL-1ra; because the same pattern is not seen at synonymous sites, it must be due not to a difference in mutation rate but rather to a greater degree of functional constraint on this region in the IL-1 beta and IL-1ra proteins than in the IL-1 alpha protein. But synonymous sites in IL-1 beta of mouse have evolved more rapidly than in IL-1 beta of human, indicating a higher rate of mutation in the former gene. In the N-terminal region of the protein, nonsynonymous sites have evolved at similar rates in IL-1 alpha and IL-1 beta. The first exon of the IL-1ra gene, which encodes the leader peptide, shows evidence of homology with the first exon of IL-1 beta, which is not translated. Thus, it seems likely that IL-1ra evolved by duplication of an IL-1 beta gene and loss of expression of exons 2-4.

An upstream protein interacts with a distinct protein that binds to the cap site of the human interleukin 1 beta gene

Interleukin 1 beta (IL-1 beta) is a proinflammatory cytokine that exhibits a wide variety of biological activities. Genomic sequences that mediate the induction of human IL-1 beta gene transcription by lipopolysaccharide and phorbol esters are located more than 2,700 bp upstream of the transcriptional start site (cap site). These upstream elements require additional cap site-proximal (CSP) sequences which are necessary for basal transcription of the human IL-1 beta gene. In addition, these CSP sequences have been shown to mediate both cell type-specific expression of this gene, and trans-activation by some viral proteins. In this study, we report the identification of a novel nuclear protein, termed NF beta C, that binds to a DNA sequence which spans the cap site of the human IL-1 beta gene (positions -12 to +8). We have also identified a second region (positions -305 to -280) containing a putative NF-kappa B binding site. We show here that this region can bind three distinct nuclear proteins. One protein is similar or identical to NF-kappa B, a second protein (termed NF beta B) binds a distinct sequence that substantially overlaps the 5' half of the NF kappa B binding sequence, and a third protein (termed NF beta D) binds a distinct sequence that substantially overlaps the 3' half of the NF kappa B binding sequence. Unlike NF kappa B, NF1 beta B and NF beta D are present in nuclear extracts prepared from unstimulated monocytic cells. Although the NF beta D and NF beta C binding sequences share no significant similarity, each sequence can specifically compete for the binding of either protein to DNA, whereas oligonucleotides containing only the NF kappa B or NF beta B motifs do not compete for the binding of NF beta C or NF beta D. This suggests that NF beta C and NF beta D can specifically interact in vitro, possibly through a common subunit.

The mouse interleukin 1 receptor antagonist protein: gene structure and regulation in vitro

The interleukin 1 receptor antagonist (IL-1ra) protein is an inhibitor of the pro-inflammatory cytokine interleukin 1. We have sequenced the mouse gene encoding the monocyte form of IL-1ra (IL-1rn) and compared it with the sequence of the human homologue. In addition to high levels of similarity between the coding regions of the two genes, portions of the introns show surprisingly high levels of identity. In order to develop an in vitro model system to investigate the regulation of IL-1ra induction, three differently responding mouse macrophage cell lines were stimulated with lipopolysaccharide. The kinetics and magnitude of IL-1ra mRNA accumulation was cell-line specific indicating that IL-1ra synthesis in response to inducing agents varies according to the phenotype of the cell. Analysis of the relative transcription rate and the half life of the mouse IL-1ra mRNA indicate that IL-1ra mRNA accumulation in macrophages following LPS treatment is due primarily to an increase in transcription rate rather than to increased stability.

Gene sequence, cDNA construction, expression in Escherichia coli and genetically approached purification of porcine interleukin-1 beta

A genomic clone (PIL3) covering the 8.8-kb prointerleukin-1 beta ('catabolin') gene of the domesticated swine (Sus scrofa domestica) was isolated from a genomic library and characterized by nucleotide sequencing. Typical features of the gene include a seven-exon structure, with the highest degree of nucleotide and amino acid conservation among human and porcine genes being found in the receptor-binding portion encoded by exons six and seven. Three 250-bp repetitive elements with a > 75% similarity to the pig repetitive element-1 family sequence are located in untranslated gene segments. Southern-hybridization experiments disclosed extensive genomic heterogeneity of the porcine interleukin-1 beta (IL-1 beta) gene region, suggesting a duplication of at least the 3' half of the gene in the porcine genome. Since similar hybridization patterns were observed for wild boar (Sus scrofa) genomic DNA, it was concluded that this gene rearrangement had preceded domestication of the wild swine. In addition, the cDNA for processed porcine IL-1 beta was constructed through polymerase-chain-reaction-mediated exon fusion by overlap extension starting from the genomic template. Recombinant IL-1 beta was expressed in Escherichia coli as a fusion protein containing an N-terminal hexahistidine tag followed by a factor-Xa-cleavage site. The protein was efficiently purified through adoption of a scheme that consisted of four alternating cycles of immobilized metal-ion-affinity chromatography and size-exclusion chromatography. 13.8 mg highly purified recombinant porcine IL-1 beta was obtained starting from a 900-ml thermo-induced E. coli culture (final endotoxin concentration < 0.22 ng/ml). The protein behaved homogeneously as a monomeric species, which was reactive in Western-blot experiments with an anti-(human-IL-1 beta) serum and which appeared to induce gelatinase B in MDBK cells in a dose-dependent fashion.

Disruption in the AU motif of the mouse TNF-alpha 3' UTR correlates with reduced TNF production by macrophages in vitro

Many cytokine mRNAs exhibit a conserved, AU-rich motif in the 3'-untranslated region (UTR) of the molecule. Such sequence elements have been implicated in the regulation of mRNA turnover and as potential translational regulators. We report on the identification of a 3 base pair insertion which disrupts the AU motif of the TNF-alpha gene in the NZW, B10.KPA44, SM/J and Mus spretus mice and an insertion of an 8 base pair sequence into the 3' AU motif of the IL-10 gene in the Mus Spretus mouse. The mutation in the AU motif of the TNF-alpha gene correlates with reduced production of this cytokine by peritoneal macrophages from these mouse strains.

The functional importance of a cap site-proximal region of the human prointerleukin 1 beta gene is defined by viral protein trans-activation

Prointerleukin 1 beta (IL-1 beta) is a cytokine that mediates a broad range of biological activities. Genomic sequences that regulate IL-1 beta transcription include both inducible regulatory elements located more than 2,700 bp upstream of the transcriptional start site (cap site) and proximal elements located near the TATA box of this gene. In this study, we focused on the identification and characterization of trans-acting nuclear regulatory proteins that bind to the cap site-proximal region of the human IL-1 beta gene. We identified a protein, termed NFIL-1 beta A (NF beta A), that binds to a highly conserved 12-bp DNA sequence (-49 to -38) located upstream of the TATA box motif in both the human and murine IL-1 beta genes. The IL-1 alpha gene, which lacks a TATA motif, does not possess an NF beta A-binding sequence within the promoter region, suggesting that NF beta A may selectively regulate IL-1 beta expression. Using electrophoretic mobility shift assays, we identified several distinct DNA-protein complexes that are expressed in a cell-type-specific manner. In monocytic cell lines, the relative abundance of these complexes varies rapidly following stimulation of the cells with phorbol esters or lipopolysaccharide. UV cross-linking analysis identified two distinct DNA-binding polypeptides that comprise distinct complexes. The functional role of NF beta A was assessed in transient transfection assays. These data indicate that NF beta A is required for both basal and inducible promoter activity in monocytic cells. Furthermore, the human cytomegalovirus immediate-early 1 gene product requires the presence of NF beta A in order to trans-activate the proximal IL-1 beta promoter in a monocytic cell line. We propose that NF beta A is a factor that mediates either direct or indirect activation by the immediate-early 1 gene product. The proximity of this essential factor to the TATA motif suggests a possible role in transcriptional initiation.

The functional importance of a cap site-proximal region of the human prointerleukin 1 beta gene is defined by viral protein trans-activation

Prointerleukin 1 beta (IL-1 beta) is a cytokine that mediates a broad range of biological activities. Genomic sequences that regulate IL-1 beta transcription include both inducible regulatory elements located more than 2,700 bp upstream of the transcriptional start site (cap site) and proximal elements located near the TATA box of this gene. In this study, we focused on the identification and characterization of trans-acting nuclear regulatory proteins that bind to the cap site-proximal region of the human IL-1 beta gene. We identified a protein, termed NFIL-1 beta A (NF beta A), that binds to a highly conserved 12-bp DNA sequence (-49 to -38) located upstream of the TATA box motif in both the human and murine IL-1 beta genes. The IL-1 alpha gene, which lacks a TATA motif, does not possess an NF beta A-binding sequence within the promoter region, suggesting that NF beta A may selectively regulate IL-1 beta expression. Using electrophoretic mobility shift assays, we identified several distinct DNA-protein complexes that are expressed in a cell-type-specific manner. In monocytic cell lines, the relative abundance of these complexes varies rapidly following stimulation of the cells with phorbol esters or lipopolysaccharide. UV cross-linking analysis identified two distinct DNA-binding polypeptides that comprise distinct complexes. The functional role of NF beta A was assessed in transient transfection assays. These data indicate that NF beta A is required for both basal and inducible promoter activity in monocytic cells. Furthermore, the human cytomegalovirus immediate-early 1 gene product requires the presence of NF beta A in order to trans-activate the proximal IL-1 beta promoter in a monocytic cell line. We propose that NF beta A is a factor that mediates either direct or indirect activation by the immediate-early 1 gene product. The proximity of this essential factor to the TATA motif suggests a possible role in transcriptional initiation.

Review: transcriptional and post-transcriptional regulation of interleukin 1 gene expression

Interleukin 1 alpha (IL-1 alpha) and beta (IL-1 beta) are proinflammatory cytokines that are encoded by distinct genes, but share most biological activities. During the past several years, intense investigation has focused on elucidating the molecular basis for the regulation of IL-1 alpha and beta gene expression. While the overall organization of both genes is conserved in mammals, the DNA sequence homology is surprisingly limited. This supports the growing body of evidence suggesting that each gene is regulated by distinct cis- and transacting elements. Most recently, novel regulatory DNA sequence elements and several nuclear regulatory proteins have been identified, which ultimately participate in the control of IL-1 beta gene transcription. In addition to transcriptional controls, the stability of IL-1 mRNA can be selectively regulated by various inducing stimuli and other cytokines. Taken together, these transcriptional and post-transcriptional regulatory mechanisms provide stringent, yet flexible, control over expression of the IL-1 alpha and beta genes.

Distribution of simple repetitive (TG/CA)n and (CT/AG)n sequences in human and rodent genomes

Sixteen million nucleotide sequence of genome of various organisms have been analysed to detect and study the extent of occurrence of simple repetitive sequences. Two sequence motifs (TG/CA)n and (CT/AG)n capable of adopting unusual DNA structures, left handed Z-conformation and triple-helical conformation respectively, are found to be abundant in rodent and human genomes, but almost completely absent in bacterial genome. (TG/CA)n and (CT/AG)n sequences are present mostly in the intron or 5'/3' flanking regions of the genes. The presence of such repeat motifs in genomic sequence of higher eukaryotes has been correlated with their possible functional significance in nucleosome organization, recombination and gene expression.

Interleukin 1 receptor antagonist is a member of the interleukin 1 gene family: evolution of a cytokine control mechanism

Interleukin 1 receptor antagonist (IL-1ra) is a protein that binds to the IL-1 receptor and blocks the binding of both IL-1 alpha and -beta without inducing a signal of its own. Human IL-1ra has some sequence identity to human IL-1 beta, but the evolutionary relationship between these proteins has been unclear. We show that the genes for human, mouse, and rat IL-1ra are similar to the genes for IL-1 alpha and IL-1 beta in intron-exon organization, indicating that gene duplication events were important in the creation of this gene family. Furthermore, an analysis of sequence comparisons and mutation rates for IL-1 alpha, IL-1 beta, and IL-1ra suggests that the duplication giving rise to the IL-1ra gene was an early event in the evolution of the gene family. Comparisons between the mature sequences for IL-1ra, IL-1 alpha, and IL-1 beta suggest that IL-1ra has a beta-stranded structure like to IL-1 alpha and IL-1 beta, consistent with the three proteins being related. The N-terminal sequences of IL-1ra appear to be derived from a region of the genome different than those of IL-1 alpha and IL-1 beta, thus explaining their different modes of biosynthesis and suggesting an explanation for their different biological activities.

Induction of interleukin-1 beta mRNA in adult rat brain

The ability of the central nervous system to produce the cytokine interleukin-1 beta (IL-1 beta) in response to challenge by activators of the mononuclear phagocyte system has been examined in vivo. Unilateral injection of a mixture of gamma-interferon (IFN-gamma) and lipopolysaccharide (LPS) into the forebrain of adult rats induced expression of IL-1 beta mRNA. In situ hybridization of IL-1 beta mRNA showed a gradient of cellular hybridization, which was most intense at the site of IFN-gamma/LPS injection. The reverse transcription--polymerase chain reaction (RT-PCR) was used to demonstrate the presence of IL-1 beta mRNA in normal rat brain, and to confirm increases in IL-1 beta mRNA levels following IFN-gamma/LPS injection. These studies show that IL-1 beta can be induced to high levels within the CNS as a consequence of exposure to potent stimulators of macrophage activation.

Functional analysis and nucleotide sequence of the promoter region of the murine hck gene

The structure and function of the promoter region and exon 1 of the murine hck gene have been characterized in detail. RNase protection analysis has established that hck transcripts initiate from heterogeneous start sites located within the hck gene. Fusion gene constructs containing hck 5'-flanking sequences and the bacterial Neor gene have been introduced into the hematopoietic cell lines FDC-P1 and WEHI-265 by using a self-inactivating retroviral vector. The transcriptional start sites of the fusion gene are essentially identical to those of the endogenous hck gene. Analysis of infected WEHI-265 cell lines treated with bacterial lipopolysaccharide (LPS) reveals a 3- to 5-fold elevation in the levels of endogenous hck mRNA and a 1.4- to 2.6-fold increase in the level of Neor fusion gene transcripts, indicating that hck 5'-flanking sequences are capable of conferring LPS responsiveness on the Neor gene. The 5'-flanking region of the hck gene contains sequences similar to an element which is thought to be involved in the LPS responsiveness of the class II major histocompatibility gene A alpha k. A subset of these sequences are also found in the 5'-flanking regions of other LPS-responsive genes. Moreover, this motif is related to the consensus binding sequence of NF-kappa B, a transcription factor which is known to be regulated by LPS.

Functional analysis and nucleotide sequence of the promoter region of the murine hck gene

The structure and function of the promoter region and exon 1 of the murine hck gene have been characterized in detail. RNase protection analysis has established that hck transcripts initiate from heterogeneous start sites located within the hck gene. Fusion gene constructs containing hck 5'-flanking sequences and the bacterial Neor gene have been introduced into the hematopoietic cell lines FDC-P1 and WEHI-265 by using a self-inactivating retroviral vector. The transcriptional start sites of the fusion gene are essentially identical to those of the endogenous hck gene. Analysis of infected WEHI-265 cell lines treated with bacterial lipopolysaccharide (LPS) reveals a 3- to 5-fold elevation in the levels of endogenous hck mRNA and a 1.4- to 2.6-fold increase in the level of Neor fusion gene transcripts, indicating that hck 5'-flanking sequences are capable of conferring LPS responsiveness on the Neor gene. The 5'-flanking region of the hck gene contains sequences similar to an element which is thought to be involved in the LPS responsiveness of the class II major histocompatibility gene A alpha k. A subset of these sequences are also found in the 5'-flanking regions of other LPS-responsive genes. Moreover, this motif is related to the consensus binding sequence of NF-kappa B, a transcription factor which is known to be regulated by LPS.

Crystallographic refinement of interleukin 1 beta at 2.0 A resolution

The structure of human recombinant interleukin 1 beta (IL-1 beta) has been refined by a restrained least-squares method to a crystallographic R factor of 17.2% to 2.0 A resolution. One-hundred sixty-eight solvent molecules have been located, and isotropic temperature factors for each atom have been refined. The overall structure is composed of 12 beta-strands that can best be described as forming the four triangular faces of a tetrahedron with hydrogen bonding resembling normal antiparallel beta-sheets only at the vertices. The interior of this tetrahedron is filled by hydrophobic side chains. Analysis of sequence alignments with IL-1 beta from other mammalian species shows the interior to be very well conserved with the exterior residues markedly less so. There does not appear to be a clustering of invariant amino acid side chains on the surface of the molecule, suggesting an area of interaction with the IL-1 receptor. Comparison of the IL-1 beta structure with IL-1 alpha sequences indicates that IL-1 alpha probably has a similar overall folding as IL-1 beta but binds to the receptor in a different fashion. The three-dimensional structure of the IL-1 beta is analyzed in light of what has been suggested by previously published work on mutants and fragments of the molecule.

Functional and molecular characterization of a monoclonal antibody against the 165-186 peptide of human IL-1 beta

A synthetic peptide of human recombinant interleukin 1 beta (hrIL-1 beta) 165-186, which exhibits biological activity in the human fibroblast assay, was used as an immunizing antigen to obtain a murine monoclonal antibody (MoAb) termed FIB 1. This MoAb, an IgG1, reacts specifically with hrIL-1 beta, but not with hrIL-1 alpha, as measured in enzyme-linked immunosorbent assays (ELISA). The MoAb FIB 1 detects the characteristic 17 kDa IL-1 protein in Western blots. Binding to the antigen is specific, as deduced also from the close correlation of ELISA immunoreactivity with IL-1 biological activity. The anti-IL-1 beta 165-186 Ab specifically neutralizes the biological activity of hrIL-1 beta and native IL-1, as measured by the IL-1-induced proliferation of murine thymocytes and human fibroblasts and the IL-1-dependent IL-2 production by murine T cells (EL4-6.1). Fifty per cent of hrIL-1 beta activity (25 U/ml, or 0.25 ng/ml) has neutralized by less than 30 micrograms/ml of MoAb. Furthermore, FIB 1 recognizes intracellular IL-1 in lipopolysaccharide-stimulated human peripheral blood mononuclear cells. The anti-IL-1 beta 165-186 Ab does not react with the shorter IL-1 beta fragment 161-173 in solid-phase ELISA, therefore the binding region seems to be localized in the amino acid sequence VALGLKEKNLYLS. A sandwich-ELISA, using a polyclonal sheep anti-IL-1 beta 251-269 Ab as the capture antibody and an anti-IL-1 beta 165-186 MoAb as the detecting probe, allowed the determination of IL-1 beta from crude culture supernatants.

The 5' splice site: phylogenetic evolution and variable geometry of association with U1RNA

The 5' splice site sequences of 3294 introns from various organisms (1-672) were analyzed in order to determine the rules governing evolution of this sequence, which may shed light on the mechanism of cleavage at the exon-intron junction. The data indicate that, currently, in all organisms, a common sequence 1GUAAG6U and its derivatives are used as well as an additional sequence and its derivatives, which differ in metazoa (G/1GUgAG6U), lower eucaryotes (1GUAxG6U) and higher plants (AG/1GU3A). They all partly resemble the prototype sequence AG/1GUAAG6U whose 8 contigous nucleotides are complementary to the nucleotides 4-11 of U1RNA, which are perfectly conserved in the course of phylogenetic evolution. Detailed examination of the data shows that U1RNA can recognize different parts of 5' splice sites. As a rule, either prototype nucleotides at position -2 and -1 or at positions 4, 5 or 6 or at positions 3-4 are dispensable provided that the stability of the U1RNA-5' splice site hybrid is conserved. On the basis of frequency of sequences, the optimal size of the hybridizable region is 5-7 nucleotides. Thus, the cleavage at the exon-intron junction seems to imply, first, that the 5' splice site is recognized by U1RNA according to a "variable geometry" program; second, that the precise cleavage site is determined by the conserved sequence of U1RNA since it occurs exactly opposite to the junction between nucleotides C9 and C10 of U1RNA. The variable geometry of the U1RNA-5' splice site association provides flexibility to the system and allows diversification in the course of phylogenetic evolution.

Expression of membrane interleukin 1 by fibroblasts transfected with murine pro-interleukin 1 alpha cDNA

Studies of interleukin 1 (IL-1) alpha and beta have emphasized their functional similarities. IL-1 alpha and -beta are encoded by ancestrally related genes that have diverged dramatically in primary sequence; however, only modest differences in the regulation or biological activity of IL-1 alpha and IL-1 beta have been documented. Here we show that mouse L cells transfected with murine pro-IL-1 alpha cDNA expressed biologically active, 33-kilodalton pro-IL-1 alpha, and that this pro molecule was neither processed to the 17-kilodalton mature form nor secreted. The transfected cells also expressed membrane-associated IL-1 biological activity, indicating that the pro-IL-1 alpha cDNA can direct expression of membrane-associated IL-1 and that cleavage of the pro molecule is not required for membrane presentation. In contrast, transfection of pro-IL-1 beta cDNA did not generate biologically active material in L cells. Evidence is presented that the native murine IL-1 beta precursor molecule is also biologically inactive in peritoneal exudate cells stimulated with lipopolysaccharide. These differences in distribution of the bioactive forms of IL-1 alpha and IL-1 beta may provide selective advantages for the maintenance of two gene products with similar functions.

Human interleukin-1 beta gene

We report the nucleotide sequence of the human chromosomal gene which encodes the interleukin-1 beta protein (IL-1 beta). The gene spans a region of 7.5 kb and the coding part is divided into seven exons. Comparison with the homologous mouse gene reveals that the structural organization is conserved through evolution. In addition to this, human and murine IL-1 beta genes show extensive sequence homology within the intervening sequences.