ABSTRACT
BACKGROUND AND AIMS: Subclinical Vitamin B12 deficiency is a very common entity in the Indian subcontinent with devastating clinical and socio-economic consequences. The objective of this study was to estimate the proportion of vitamin B12 deficient children and to evaluate their clinical profile. SETTING AND DESIGN: This prospective analytical study was conducted in a tertiary level care institute in Northern India. MATERIALS AND METHODS: Children with clinical pallor, were included in this study. Detailed history, height, weight percentiles and characteristic features of vitamin B12 deficiency were recorded and complete blood counts, mean corpuscular volume and vitamin B12 levels were done. STATISTICS: For Qualitative data was analyzed using Pearson Chi square tests and quantitative data was analyzed using two sided independent samples t tests. RESULTS: A total of 111 children were included. 64.8% (n = 72) had vitamin B12 deficiency. Lethargy (63.9%) and weight loss (62.1%), Knuckle pigmentation were common features. One-fourth of the children were on vegetarian diet. Neurological manifestations were significantly associated with fragile hair (p 0.056) and knuckle pigmentation (p 0.027). Younger children had more weight loss (p 0.001), knuckle pigmentation (p 0.019) and hypotonia (p 0.045). One fifth of children presented with neurological manifestations. CONCLUSIONS: Two-thirds of the anemic children had vitamin B12 deficiency. There was a bimodal age distribution with regard to B12 deficiency. Neurological manifestations were predominant in younger children [<6] and hematological abnormalities were more frequent in older children [≥6 years]. Estimation of vitamin B12 levels forms an essential component while evaluating children with anemia, despite mixed dietary habits and normal MCV.
ABSTRACT
Positive serology for dengue and/or scrub typhus infection with/without positive malarial smear (designated as mixed or co-infection) is being increasingly observed during epidemics of acute undifferentiated febrile illnesses (AUFIs). We planned to study the clinical and biochemical spectrum of co-infections with Plasmodium sp., dengue virus and scrub typhus and compare these with mono-infection by the same organisms. During the period from December 2012 to December 2013, all cases presenting with AUFIs to a single medical unit of a referral centre in Garhwal region of the north Indian state of Uttarakhand were retrospectively selected and categorised aetiologically as co-infections, malaria, dengue or scrub typhus. The groups thus created were compared in terms of demographic, clinical, biochemical and outcome parameters. The co-infection group (n = 49) was associated with milder clinical manifestations, fewer, milder and non-progressive organ dysfunction, and lesser need for intensive care, mechanical ventilation and dialysis as compared to mono-infections. When co-infections were sub-grouped and compared with the relevant mono-infections, there were differences in certain haematological and biochemical parameters; however, this difference did not translate into differential outcomes. Scrub typhus mono-infection was associated with severe disease in terms of both morbidity and mortality. Malaria, dengue and scrub typhus should be routinely tested in all patients with AUFIs. Co-infections, whether true or due to serological cross-reactivity, appear to be a separate entity so far as presentation and morbidity is concerned. Further insight is needed into the mechanism and identification of the protective infection.
Subject(s)
Coinfection/epidemiology , Dengue/epidemiology , Fever of Unknown Origin/epidemiology , Malaria/epidemiology , Scrub Typhus/epidemiology , Adolescent , Adult , Aged , Dengue/complications , Dengue/pathology , Female , Fever of Unknown Origin/etiology , Hospitals , Humans , India/epidemiology , Malaria/complications , Malaria/pathology , Male , Middle Aged , Retrospective Studies , Scrub Typhus/complications , Scrub Typhus/pathology , Young AdultABSTRACT
Prebiotic fructans are nondigestible carbohydrates with numerous health benefits. Soybean is a rich source of phytonutrients such as isoflavones. The objective of this study was to evaluate the chemopreventive effects of prebiotics (Synergy1) and soybean meal (SM) at 5% and 10% levels alone and in combination on azoxymethane- (AOM-) induced colon carcinogenesis. After one wk of acclimatization, Fisher 344 male rats (N = 90) were randomly assigned to 9 groups (n = 10). Control rats (C) were fed AIN-93G/M. Two s/c injections of AOM were administered to rats at 7 and 8 wk of age at 16 mg/kg body weight. Rats were killed by CO(2) asphyxiation at 45 wk. Tumor incidence (%) in treatment groups ranged from 40 to 75 compared to 100 in C. Results indicate that feeding prebiotics and soybean in combination significantly reduced incidence of AOM-induced colon tumors with implications for food industry in the food-product development.
ABSTRACT
Microarray technology was evaluated for usefulness in assessing relationships between serum corticosterone and hepatic gene expression. Nine pairs of female Swiss mice were chosen to provide a wide range of serum corticosterone ratios; cDNA microarray analysis (approximately 8000 genes) was performed on their livers. A statistical method based on calculation of 99% confidence intervals discovered 32 genes which varied significantly among the livers. Five of these ratios correlated significantly with serum corticosterone ratio, including tyrosine aminotransferase, stress-induced protein, pleiotropic regulator 1 and insulin-like growth factor-binding protein-1; the latter has a potential role in cancer development. Secondly, linear regression of gene expression vs corticosterone ratios was screened for those with r> or =0.8 (P<0.01), yielding 141 genes, including some known to be corticosterone regulated and others of interest as possible glucocorticoid targets. Half of these significant correlations involved data sets where no microarray ratio exceeded +/- 1.5. These results showed that microarray may be used to survey tissues for changes in gene expression related to serum hormones, and that even small changes in expression can be of statistical significance in a study with adequate numbers of replicate samples.
Subject(s)
Corticosterone/blood , Gene Expression Regulation, Neoplastic/genetics , Insulin-Like Growth Factor Binding Protein 1/metabolism , Liver/metabolism , Animals , Apoptosis Regulatory Proteins , Carrier Proteins/genetics , Carrier Proteins/metabolism , Female , Gene Expression Profiling/methods , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Insulin-Like Growth Factor Binding Protein 1/genetics , Mice , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Oligonucleotide Array Sequence Analysis/methods , Tyrosine Transaminase/genetics , Tyrosine Transaminase/metabolismABSTRACT
To evaluate the association between CYP1A1 genotype and lung cancer risk and to assess the effect of CYP1A1 genotype and antioxidant supplementation on the smoking--lung cancer relationship we conducted a case-control study nested within a large cancer prevention trial cohort. Controls (n = 324) were matched to cases (n = 282) on age (+/- 5 years), intervention group and study clinic in a 1:1 ratio, using incidence density sampling. Genotype was determined by a PCR-based method and logistic regression was used to calculate relative risk estimates. Overall, we found no association between CYP1A1 genotype and lung cancer risk. CYP1A1 genotype did not modify the effect of smoking on lung cancer risk. However, in an examination of subgroups defined by randomized intervention assignment our findings suggest that alpha-tocopherol supplementation may reduce the risk of lung cancer associated with cumulative smoking exposure regardless of CYP1A1 genotype with the greatest effect seen among those with the variant CYP1A1 allele.
Subject(s)
Antioxidants/pharmacology , Cytochrome P-450 CYP1A1/genetics , Lung Neoplasms/genetics , Polymorphism, Genetic , Smoking , Vitamin E/pharmacology , beta Carotene/pharmacology , Aged , Alleles , Amino Acid Substitution , Case-Control Studies , Cytochrome P-450 CYP1A1/physiology , Humans , Isoleucine/genetics , Isoleucine/physiology , Lung Neoplasms/prevention & control , Male , Middle Aged , Risk Factors , Smoking/genetics , Valine/genetics , Valine/physiologyABSTRACT
We demonstrate that dexamethasone-mediated transcription activation of the cytochrome P-450c27 promoter involves a physical interaction and functional synergy between glucocorticoid receptor (GR) and Ets2 factor. Ets2 protein binding to a "weak" Ets-like site of the promoter is dependent on GR bound to the adjacent cryptic glucocorticoid response element. Coimmunoprecipitation and chemical cross-linking experiments show physical interaction between GR and Ets2 proteins. Mutational analyses show synergistic effects of Ets2 and GR in dexamethasone-mediated activation of the cytochrome P-450c27 promoter. The DNA-binding domain of GR, lacking the transcription activation and ligand-binding domains, was fully active in synergistic activation of the promoter with intact Ets2. The DNA-binding domain of Ets2 lacking the transcription activation domain showed a dominant negative effect on the transcription activity. Finally, a fusion protein consisting of the GR DNA-binding domain and the transcription activation domain of Ets2 fully supported the transcription activity, suggesting a novel synergy between the two proteins, which does not require the transactivation domain of GR. Our results also provide new insights on the role of putative weak consensus Ets sites in transcription activation, possibly through synergistic interaction with other gene-specific transcription activators.
Subject(s)
Cytochrome P-450 Enzyme System/genetics , DNA-Binding Proteins , Proto-Oncogene Proteins/genetics , Receptors, Glucocorticoid/genetics , Repressor Proteins , Steroid Hydroxylases/genetics , Trans-Activators/genetics , Transcription Factors , Transcriptional Activation , 3T3 Cells , Animals , Cholestanetriol 26-Monooxygenase , Cytochrome P-450 Enzyme System/metabolism , Mice , Promoter Regions, Genetic/genetics , Protein Binding , Proto-Oncogene Protein c-ets-2 , Proto-Oncogene Proteins/metabolism , Rats , Receptors, Glucocorticoid/metabolism , Signal Transduction/genetics , Steroid Hydroxylases/metabolism , Trans-Activators/metabolismABSTRACT
We have previously shown that electromagnetic field (EMF) exposure induces ETS1 oncogene overexpression in different cell lines. In order to investigate in vivo EMF effects, BALB/c mice were exposed at different times to 50 MHz radiation, modulated (80%) at 16 Hz. The exposed and control animals were sacrificed and the spleen excised for rt-pcr and western blot analysis. We observed an increase in ETS1 mRNA and protein expression, but a decrease in ETS2 protein levels. Preliminary results from this experimental model show in vivo evidence of the effect of EMF on ETS oncogene expression.
Subject(s)
DNA-Binding Proteins , Electromagnetic Fields/adverse effects , Gene Expression Regulation , Proto-Oncogene Proteins/genetics , Repressor Proteins , Trans-Activators/genetics , Transcription Factors/genetics , Animals , Male , Mice , Mice, Inbred BALB C , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Protein c-ets-2 , Proto-Oncogene Proteins c-ets , RNA, MessengerABSTRACT
We have analyzed gene expression in hemopoietic and testicular cell types after their exposure to 50 MHz radiofrequency (RF) non-ionizing radiation modulated (80%) with a 16 Hz frequency. The exposure system generates a 0.2 microT magnetic field parallel to the ground and a 60 V/m electric field orthogonal to the earth's magnetic field. Exposure conditions were selected so as to interfere with the calcium ion flow. Under these electromagnetic field (EMF) conditions, we observed an overexpression of the ets1 mRNA in Jurkat T-lymphoblastoid and Leydig TM3 cell lines. This effect was observed only in the presence of the 16 Hz modulation, corresponding to the resonance frequency for calcium ion with a DC magnetic field of 45.7 microT. We have also identified a putative candidate gene repressed after EMF exposure. The experimental model described in this paper may contribute to the understanding of the biological mechanisms involved in EMF effects.
Subject(s)
Electromagnetic Fields , Oncogenes/radiation effects , Proto-Oncogene Proteins/genetics , Radio Waves , Transcription Factors/genetics , Transcription, Genetic/radiation effects , Animals , Cell Line , Colonic Neoplasms , HL-60 Cells , Humans , Jurkat Cells , Leydig Cells/metabolism , Leydig Cells/radiation effects , Male , Mice , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins c-ets , RNA, Messenger/genetics , Testis , Tumor Cells, CulturedABSTRACT
Genetic susceptibility polymorphisms may be of substantial importance in the modulation of cancer risk. The prevalence for an array of polymorphic genes was determined in a cohort of male smokers who participated in a cancer prevention trial in Finland. A random sample of 120 individuals was selected from the trial cohort and the prevalence of variant alleles for nine genes was determined using a polymerase chain reaction-based approach. The prevalence values from this study were also compared with those of other populations derived from previous studies. Our results show that, with the exception of cytochrome P450-1A1 (CYP1A1) and cytochrome P450-2E1 (CYP2E1), all genes tested were sufficiently polymorphic to warrant an investigation of gene-environment studies. Most of the variant alleles, including alcohol dehydrogenase 3 (ADH3), glutathione-S-transferase (GSTM1), methionine synthase (MS), methylene tetrahydofolater reductase (MHTFR), CYP2E1 and CYP1A1, exhibited similar frequencies to other Caucasian populations. Interestingly, the prevalence of androgen receptor-CAG repeat (AR-CAG) and vitamin D receptor (VDR) polymorphisms differed significantly between the alpha-tocopherol, beta-carotene (ATBC) Study and other Caucasian populations. We present herein results from this survey and conclude that the ATBC study population in Finland is sufficiently heterogeneous to facilitate analysis of genetic polymorphisms and disease associations.
Subject(s)
Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP2E1/genetics , DNA, Neoplasm/analysis , Genetic Predisposition to Disease , Lung Neoplasms/genetics , Neoplasms/genetics , Prostatic Neoplasms/genetics , Adult , Alleles , Base Sequence , Chi-Square Distribution , Cohort Studies , Cytochrome P-450 CYP1A1/analysis , Cytochrome P-450 CYP2E1/analysis , Enzyme Activation , Finland/epidemiology , Gene Frequency , Humans , Lung Neoplasms/epidemiology , Male , Middle Aged , Molecular Sequence Data , Neoplasms/epidemiology , Polymerase Chain Reaction , Polymorphism, Genetic , Prevalence , Prostatic Neoplasms/epidemiology , Randomized Controlled Trials as Topic , Sampling Studies , Smoking , White People/geneticsABSTRACT
The GSTM1 (glutathione S-transferase mu-1) null genotype is suspected of increasing an individual's susceptibility to tobacco smoke carcinogens because of impaired carcinogen detoxification. We were interested in whether there were differences in lung cancer susceptibility to smoking within the GSTM1 genotypes and the impact of antioxidant supplementation on this. For this purpose, we conducted a nested lung cancer case-control study and evaluated the role of GSTM1 within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. GSTM1 genotype status was determined for 319 cases and 333 controls using a PCR-based approach. GSTM1 was evaluated as an independent risk factor and as an effect modifier of smoking using logistic regression analyses. The GSTM1 null genotype itself was unrelated to risk of lung cancer, odds ratio (OR) = 1.09 and 95% confidence interval (CI), 0.79-1.50, but it may have modified the effect of smoking. There was a suggestion for a stronger association between years of smoking and lung cancer among the GSTM1 null genotype, but the differences between GSTM1 null and present genotypes were not statistically significant (P = 0.12). Furthermore, the smoking association was strongest among those with the GSTM1 null genotype not receiving alpha-tocopherol supplementation, whereas among those receiving alpha-tocopherol, there was no modification by GSTM1 on the association between smoking duration and lung cancer risk. Beta-carotene supplementation did not modify the relationship between GSTM1, smoking years, and lung cancer risk. In conclusion, GSTM1 is not associated with lung cancer risk in male smokers but may confer a higher susceptibility to cumulative tobacco exposure. This association may be attenuated by alpha-tocopherol but not by beta-carotene supplementation.
Subject(s)
Glutathione Transferase/genetics , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Smoking/adverse effects , Vitamin E/administration & dosage , beta Carotene/administration & dosage , Adult , Age Distribution , Aged , Antioxidants/administration & dosage , Case-Control Studies , Cohort Studies , Confidence Intervals , Finland/epidemiology , Genotype , Humans , Incidence , Logistic Models , Lung Neoplasms/epidemiology , Male , Middle Aged , Multivariate Analysis , Odds Ratio , Polymerase Chain Reaction , Risk Factors , Sampling StudiesABSTRACT
We have shown before that the N8 mRNA is expressed at higher levels in lung tumor and lung tumor-derived cell lines than normal lung cells. In this paper, we have characterized the N8 protein, and studied its properties. The N8 gene encodes a major 24 kDa protein and its expression correlates well with the N8 mRNA expression pattern observed in different cell lines. N8 protein is capable of forming a homodimer or multimeter in vitro. It is a phosphorylated cytoplasmic protein and phosphorylation occurs mainly at serine residues. N8 protein is expressed at higher levels in epithelial cells than in mesenchymal cells. N8 protein expression is induced in a fibroblast cell line expressing adenoviral Ela protein, which acquired epithelial-like characteristics. Furthermore, ectopic expression of N8 protein in NIH3T3 cells converts them into a spheroid form. These spheroids also have some of the characteristic features of epithelial cells. Taken together, these results suggest that the N8 protein may be associated with the development or maintenance of epithelial cell phenotype.
Subject(s)
Leucine Zippers , Neoplasm Proteins/analysis , Repressor Proteins/analysis , 3T3 Cells , Animals , Epithelial Cells/chemistry , Humans , Intestines/chemistry , Mice , Neoplasm Proteins/chemistry , Phosphorylation , Rabbits , Repressor Proteins/chemistry , Serine/metabolism , Tumor Cells, CulturedABSTRACT
We have previously shown that the human ETS1 protein (p51-ETS1), when ectopically expressed in colon cancer cell lines, is able to reduce its tumorigenicity without affecting its growth properties. To understand the mechanism of tumor reduction, we have expressed two different forms of ETS1 in colon cancer cell lines. Data presented in this paper indicate that the naturally occurring spliced variant protein, p42-ETS1, lacking the region encoded by ETS1 exon VII, represses the tumorigenicity, while p51-ETS1 reduces the tumorigenicity. Repression of tumorigenicity mediated by p42-ETS1 appears to be caused by its ability to induce apoptosis in epithelial cancer cells. This work can have profound medical significance in that it may open up new insights into the potential role of the p42-ETS1 in the induction of apoptosis in epithelial cell cancers and may provide a rationale for its use for potential gene therapy experiments to initiate cell death in cancer cells.
Subject(s)
Apoptosis/physiology , Colonic Neoplasms/pathology , Proto-Oncogene Proteins/physiology , Transcription Factors/physiology , Animals , Cell Nucleus/metabolism , Colonic Neoplasms/metabolism , Colonic Neoplasms/prevention & control , Humans , Mice , Mice, Nude , Protein Synthesis Inhibitors/pharmacology , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins/drug effects , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-ets , Tetracycline/pharmacology , Transcription Factors/chemistry , Transcription Factors/drug effects , Transcription Factors/genetics , Transfection , Tumor Cells, CulturedSubject(s)
Gene Expression Regulation , Multigene Family , Transcription Factors/genetics , Transcription Factors/metabolism , Animals , Cell Transformation, Neoplastic , Chromosome Aberrations , Genes, Tumor Suppressor , Humans , Models, Genetic , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Transcription, GeneticABSTRACT
Ewing's sarcoma family of tumors (EFT) contain reciprocal translocations, of which approximately 90% occur between the long arm of chromosomes 11 and 22,t(11;22)(q24;q12) resulting in the formation of chimeric proteins generated by a fusion of the EWS and FLI-1 genes. To determine if EWS-FLI-1 protein is responsible for the Ewing sarcoma phenotype we have used sequence-specific antisense oligodeoxynucleotides (ODN) to block its expression. We have evaluated a series of antisense ODN directed toward the breakpoint region in an effort to prevent translation of the fusion messenger RNA. ODN were first evaluated in a cell-free in vitro translation system. Exogenously added RNase H was found to be required for translation inhibition. ODN that showed complete inhibition of translation were electroporated into TC-32 cells, a EFT cell line. Fusion protein and EWS protein levels were evaluated by Western blot analysis. A 40-60% decrease in the fusion protein was observed in TC-32 cells with antisense ODN directed toward the breakpoint region. Cell viability was reduced with antisense sequences in TC-32 cells but not in a prostate cancer cell line. Since inhibition of t(11:22) gene product is correlated to effects on cell viability reduction of the fusion protein may thus offer insight into the biology of EFT.
Subject(s)
Bone Neoplasms/genetics , Oligonucleotides, Antisense/genetics , Sarcoma, Ewing/genetics , Cell Division/genetics , Cell Survival/genetics , Electroporation/standards , Gene Expression Regulation, Neoplastic/physiology , Genetic Testing , Humans , Male , Prostatic Neoplasms , Recombinant Fusion Proteins/genetics , Transcription, Genetic/genetics , Translocation, Genetic , Tumor Cells, Cultured/cytology , Tumor Cells, Cultured/physiologyABSTRACT
Using differential display method, we have isolated and characterized a novel gene, N8, encoding an approximately 24 kDa protein. It is located on human chromosome 8q13 region. N8 gene is expressed at high levels in tumor derived cell lines from multiple cancers. It is also expressed at higher levels in lung tumors than normal lung tissue. N8 is also differentially expressed in fetal and adult tissues. In adult, N8 is expressed at high levels in brain, kidney, prostate, pancreas and intestine and at very low levels in lung, liver, hematopoietic cells and gonads. During murine embryonic development N8 is expressed in the epithelium of the intestine, stomach, olfactory epithelium, neuronal layers of retina, kidney and salivary gland. Taken together, these results suggest that N8 may play different roles during embryogenesis and in the adult animals.
Subject(s)
Chromosomes, Human, Pair 8 , Neoplasm Proteins/genetics , Neoplasms/genetics , Repressor Proteins/genetics , Amino Acid Sequence , Base Sequence , Blotting, Northern , Cell Line , Chromosome Mapping , Consensus Sequence , DNA Primers , DNA, Complementary , Female , Gene Expression , Humans , In Situ Hybridization , Karyotyping , Leucine Zippers , Lung/metabolism , Lung Neoplasms/genetics , Male , Molecular Sequence Data , Neoplasms/pathology , Organ Specificity , Polymerase Chain Reaction , RNA, Messenger/analysis , RNA, Messenger/biosynthesis , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Tumor Cells, CulturedABSTRACT
Five monoclonal antibodies were produced from mice immunized with recombinant full length human ERGB protein. Among these monoclonal antibodies, four clones did not cross react with other ets family proteins and thus are specific for the ERGB protein; however, one clone did react with the ERG protein, which has high amino acid identity with the ERGB protein. The epitope location of these antibodies was studied using bacterially expressed fragments of the human, ERGB protein. These monoclonal antibodies recognized 51 kDa (p51) and 48 kDa (p48), two ERGB gene-encoded proteins, from human, mouse, and rat cell lines. These results suggest that the monoclonal antibodies can be used in human, mouse, or rat cell lines and will be useful for the biochemical and functional analysis of the ERGB protein.
Subject(s)
Antibodies, Monoclonal/biosynthesis , Antibodies, Monoclonal/chemistry , DNA-Binding Proteins/immunology , Proto-Oncogene Proteins , Trans-Activators/immunology , Animals , Cell Line , DNA-Binding Proteins/isolation & purification , Epitope Mapping , Female , Humans , Mice , Precipitin Tests , Proto-Oncogene Protein c-fli-1 , Rats , Recombinant Proteins/biosynthesis , Recombinant Proteins/immunology , Recombinant Proteins/isolation & purification , Species Specificity , Trans-Activators/isolation & purificationABSTRACT
We have ectopically expressed transcription factor ETS1 in two different highly tumorigenic human colon cancer cell lines, DLD-1 and HCT116, that do not express endogenous ETS1 protein and have obtained several independent clones. The expression of wild-type ETS1 protein in these colon cancer cells reverses the transformed phenotype and tumorigenicity in a dose-dependent manner. By contrast, expression in DLD-1 cells of a variant form of ETS1, lacking transcriptional activity, did not alter the tumorigenic properties of the cells, suggesting that the reduction in tumorigenicity in these clones was specific for the wild-type ETS1 gene products. Since these colon cancer cells have multiple genetic alterations, the system described in this paper could be a good model to study the suppression of tumorigenicity at a transcriptional level, which could lead to the design and development of novel drugs for cancer treatment.
Subject(s)
Colonic Neoplasms/pathology , Point Mutation , Proto-Oncogene Proteins/metabolism , Transcription Factors/metabolism , Base Sequence , Binding Sites , Cell Line , DNA Primers , Humans , Molecular Sequence Data , Multigene Family , Open Reading Frames , Polymerase Chain Reaction , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins/biosynthesis , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-ets , Recombinant Proteins/biosynthesis , Transfection , Tumor Cells, CulturedABSTRACT
The ETS1 gene encodes a sequence-specific transcription factor binding to purine-rich DNA sequences (-GGAA-) present in the transcriptional regulatory regions of many cellular and viral promoters/enhancers, including many lymphokine genes. The ETS1 gene is expressed at high levels in resting T cells and at very low levels after T cell activation, suggesting it may suppress the expression of genes induced during T cell activation. To find out if ETS1 regulates expression of the IL-2 gene, we have ectopically expressed antisense (AS) ETS1 in Jurkat T cells to block the formation of ETS1 proteins. AS ETS1 transfectants produce higher levels of IL-2 compared with sense ETS1 transfectants. Expression of ETS1 DNA binding domain in Jurkat T cells also decreased the production of IL-2. In AS ETS1 transfectants, IL-2 formation was completely inhibited by cyclosporin A and FK590. The IL-2 promoter linked to a chloramphenicol acetyl transferase reporter gene has high activity in AS ETS1 transfectants, indicating that increased IL-2 production seems to be a result of transcriptional induction. Taken together, these results suggest the possibility that ETS1 may act as a negative regulator of IL-2 gene transcription and provide a rational approach toward engineering the endogenous expression of IL-2 in T cells.
Subject(s)
Gene Expression Regulation/genetics , Interleukin-2/biosynthesis , Interleukin-2/genetics , Proto-Oncogene Proteins/genetics , Transcription Factors , Cell Line , Chloramphenicol O-Acetyltransferase/genetics , Humans , Ionomycin/pharmacology , Promoter Regions, Genetic/genetics , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins/biosynthesis , Proto-Oncogene Proteins/physiology , Proto-Oncogene Proteins c-ets , Tetradecanoylphorbol Acetate/pharmacology , Transcription, Genetic/genetics , Transfection/geneticsABSTRACT
The epitope for E44 monoclonal antibody (mAb) was mapped using mutated ETS1 proteins lacking different carboxy-terminal regions and by the employment of synthetic oligopeptides spanning the epitope region. This epitope lies around Arg211 of the human ETS1 protein since substitution of Arg211 by Gln211 in the epitope region results in the loss of recognition of the mouse ETS1 protein by E44 mAb. Substitution of Leu214 by valine214 in the epitope region (as is found in the chicken ETS1 and viral Ets proteins) does not alter the capacity of the E44 mAb to recognize this antigen. Taken together, these results suggest that a specific ionic interaction is able to play a pivotal role in the recognition of the ETS1 protein by the E44 mAb.
Subject(s)
Antibodies, Monoclonal/immunology , Epitopes/immunology , Peptide Fragments/immunology , Proto-Oncogene Proteins/immunology , Transcription Factors , Amino Acid Sequence , Blotting, Western , Humans , Molecular Sequence Data , Peptide Mapping , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins c-ets , Tumor Cells, CulturedABSTRACT
The interleukin-2 receptor (IL-2R) beta chain (IL-2R beta) is an essential signaling component of high- and intermediate-affinity IL-2Rs. Our laboratory previously reported that a DNA fragment containing 857 bp of 5'-flanking sequence of the human IL-2R beta gene exhibited promoter activity. We have now further characterized the promoter and delineated cis-acting regulatory regions. The region downstream of -363 is critical for basal and phorbol myristate acetate-inducible IL-2R beta promoter activity and contains at least three enhancer-like regions. Among them, the -56 to -34 enhancer was the most potent and had high-level activity in two T-cell lines but not in nonlymphoid HeLaS3 and MG63 cells. This enhancer contains a GGAA Ets binding site which bound two Ets family proteins, Ets-1 and GA-binding protein in vitro. Mutation of the Ets motif strongly diminished both promoter and enhancer activities. We conclude that this Ets binding site plays a key role in regulating basal and phorbol myristate acetate-inducible IL-2R beta promoter activity and may also contribute to tissue-specific expression of the IL-2R beta gene.