Mugwort and ragweed pollens have been considered as important respiratory allergens in Korea. These two pollens are abundant in the air of Seoul from August through October. Many ragweed-sensitive patients have shown concurrent sensitivities to mugwort pollen. However the antigenic relationship between these two pollens has not been clarified. To observe the cross-reactivity between them, we developed polyclonal anti-mugwort and anti-ragweed antibodies by immunization on New Zealand white rabbits, and performed crossed immunoelectrophoresis(CIE) with two pollen extracts. Five precipitation lines were formed by mugwort and anti-mugwort antibody. One precipitation line was formed by ragweed and anti-ragweed antibody. There was no reaction from mugwort and anti-ragweed antibody, and from ragweed and anti-mugwort antibody. These results indicate that there is no cross-antigenicity between mugwort and ragweed pollens.
Animal ; Antibodies/immunology ; Cross Reactions ; Immunoelectrophoresis, Two-Dimensional ; Pollen/*immunology ; Rabbits

BACKGROUNDThe acute myeloid leukemia 1 (AML1)-eight-twenty-one (ETO) fusion protein generated by the t(8;21)(q22;q22) translocation is considered to display a crucial role in leukemogenesis in AML. By focusing on the anti-leukemia effects of eyes absent 4 (EYA4) gene on AML cells, we investigated the biologic and molecular mechanism associated with AML1-ETO expressed in t(8;21) AML.

METHODSQualitative polymerase chain reaction (PCR), quantitative reverse transcription PCR (RT-PCR), and Western blotting analysis were used to observe the mRNA and protein expression levels of EYA4 in cell lines. Different plasmids (including mutant plasmids) of dual luciferase reporter vector were built to study the binding status of AML1-ETO to the promoter region of EYA4. Chromatin immunoprecipitation assay was used to study the epigenetic silencing mechanism of EYA4. Bisulfite sequencing was applied to detect the methylation status in EYA4 promoter region. The influence of EYA4 gene in the cell proliferation, apoptosis, and cell clone-forming ability was detected by the technique of Cell Counting Kit-8, flow cytometry, and clonogenic assay.

RESULTSEYA4 gene was hypermethylated in AML1-ETO+ patients and its expression was down-regulated by 6-fold in Kasumi-1 and SKNO-1 cells, compared to HL-60 and SKNO-1-siA/E cells, respectively. We demonstrated that AML1-ETO triggered the epigenetic silencing of EYA4 gene by binding at AML1-binding sites and recruiting histone deacetylase 1 and DNA methyltransferases. Enhanced EYA4 expression levels inhibited cellular proliferation and suppressed cell colony formation in AML1-ETO+ cell lines. We also found EYA4 transfection increased apoptosis of Kasumi-1 and SKNO-1 cells by 1.6-fold and 1.4-fold compared to negative control, respectively.

CONCLUSIONSOur study identified EYA4 gene as targets for AML1-ETO and indicated it as a novel tumor suppressor gene. In addition, we provided evidence that EYA4 gene might be a novel therapeutic target and a potential candidate for treating AML1-ETO+ t (8;21) AML.

Apoptosis ; genetics ; physiology ; Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; genetics ; physiology ; Chromatin Immunoprecipitation ; Core Binding Factor Alpha 2 Subunit ; genetics ; metabolism ; DNA Methylation ; genetics ; Epigenesis, Genetic ; genetics ; Gene Silencing ; HL-60 Cells ; Humans ; Leukemia, Myeloid, Acute ; genetics ; metabolism ; pathology ; Oncogene Proteins, Fusion ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; RUNX1 Translocation Partner 1 Protein ; Radioimmunoprecipitation Assay ; Trans-Activators ; genetics ; metabolism

Nowadays, huge volumes of chromatin immunoprecipitation-sequencing (ChIP-Seq) data are generated to increase the knowledge on DNA-protein interactions in the cell, and accordingly, many tools have been developed for ChIP-Seq analysis. Here, we provide an example of a streamlined workflow for ChIP-Seq data analysis composed of only four packages in Bioconductor: dada2, QuasR, mosaics, and ChIPseeker. ‘dada2’ performs trimming of the high-throughput sequencing data. ‘QuasR’ and ‘mosaics’ perform quality control and mapping of the input reads to the reference genome and peak calling, respectively. Finally, ‘ChIPseeker’ performs annotation and visualization of the called peaks. This workflow runs well independently of operating systems (e.g., Windows, Mac, or Linux) and processes the input fastq files into various results in one run. R code is available at github: https://github.com/ddhb/Workflow_of_Chipseq.git.
Chromatin ; Chromatin Immunoprecipitation ; Genome ; Quality Control ; Statistics as Topic*

Recent technical advances, such as chromatin immunoprecipitation combined with DNA microarrays (ChIp-chip) and chromatin immunoprecipitation-sequencing (ChIP-seq), have generated large quantities of high-throughput data. Considering that epigenomic datasets are arranged over chromosomes, their analysis must account for spatial or temporal characteristics. In that sense, simple clustering or classification methodologies are inadequate for the analysis of multi-track ChIP-chip or ChIP-seq data. Approaches that are based on hidden Markov models (HMMs) can integrate dependencies between directly adjacent measurements in the genome. Here, we review three HMM-based studies that have contributed to epigenetic research, from a computational perspective. We also give a brief tutorial on HMM modelling-targeted at bioinformaticians who are new to the field.
Chromatin ; Chromatin Immunoprecipitation ; Classification ; Dataset ; Epigenomics* ; Genome ; Oligonucleotide Array Sequence Analysis

Human papillomavirus (HPV) 16, E7 proteins derived from the prototype (Bac73) and natural variant (Bac101) E7 open reading frame were produced in Sf9 insect cells. The variant E7 gene occurred naturally by substitution mutation at the position of 88 nucleotide, resulting serine instead of asparagine. Using E7 specific monoclonal antibody (VD6), both E7 proteins were identified in recombinant baculovirus infected SF9 cells. Radiolabelling and immunoprecipitation analysis revealed that both E7 proteins were phosphoproteins. Immunostaining result showed that E7 proteins were mainly localized in the cytoplasm. Nuclear form of E7 proteins was also detected after a sequential fractionation procedure for removing chromatin structure. Considering that the VD6 recognition site in E7 protein is located within 10 amino acid at the N-terminus, this region appears to be blocked by the nuclear component. Western blot analysis revealed that nuclear form was more abundant than cytoplasmic E7 proteins. Time course immunostaining showed that the primary location of E7 protein was the nucleus and exported to the cytoplasm as proteins were accumulated. These events occurred similarly in both Bac73 and Bac101 infected Sf9 cells, suggesting that these two proteins may have similar biological functions.
Asparagine ; Baculoviridae* ; Blotting, Western ; Chromatin ; Cytoplasm ; Humans* ; Immunoprecipitation ; Insects ; Open Reading Frames ; Phosphoproteins ; Serine ; Sf9 Cells

Notch1 has been reported to be highly expressed in triple-negative and other subtypes of breast cancer. Mutant p53 (R280K) is overexpressed in MDA-MB-231 triple-negative human breast cancer cells. The present study aimed to determine whether the mutant p53 can be a potent transcriptional activator of the Notch1 in MDA-MB-231 cells, and explore the role of this mutant p53-Notch1 axis in curcumin-induced apoptosis. We found that curcumin treatment resulted in an induction of apoptosis in MDA-MB-231 cells, together with downregulation of Notch1 and its downstream target, Hes1. This reduction in Notch1 expression was determined to be due to the decreased activity of endogenous mutant p53. We confirmed the suppressive effect of curcumin on Notch1 transcription by performing a Notch1 promoter-driven reporter assay and identified a putative p53-binding site in the Notch1 promoter by EMSA and chromatin immunoprecipitation analysis. Overexpression of mutant p53 increased Notch1 promoter activity, whereas knockdown of mutant p53 by small interfering RNA suppressed Notch1 expression, leading to the induction of cellular apoptosis. Moreover, curcumin-induced apoptosis was further enhanced by the knockdown of Notch1 or mutant p53, but it was decreased by the overexpression of active Notch1. Taken together, our results demonstrate, for the first time, that Notch1 is a transcriptional target of mutant p53 in breast cancer cells and suggest that the targeting of mutant p53 and/or Notch1 may be combined with a chemotherapeutic strategy to improve the response of breast cancer cells to curcumin.
Apoptosis ; Axis, Cervical Vertebra ; Breast ; Breast Neoplasms ; Chromatin Immunoprecipitation ; Curcumin ; Down-Regulation ; Humans ; RNA, Small Interfering

OBJECTIVE: To optimize DNA library construction in non-crosslinked chromatin immunoprecipitation coupled with next-generation sequencing (Native ChIP-seq) to obtain high-quality Native ChIP-seq data. METHODS: Human nasopharyngeal carcinoma HONE1 cell lysate was digested with MNase for release of the nucleosomes, and the histone-DNA complexes were immunoprecipitated with specific antibodies. The protein component in the precipitate was digested with proteinase K followed by DNA purification; the DNA library was constructed for sequence analysis. RESULTS: Compared with the conventional DNA library construction, Tn5 transposase method allowed direct enrichment of the target DNA after Tn5 fragmentation, which was simple, time-saving and more efficient. The IGV visualized map showed that the information obtained by the two library construction methods was consistent. The sequencing data obtained by the two methods revealed more signal enrichment with Tn5 transposase library construction than with the conventional approach. H3K4me3 ChIP results showed a good reproducibility after Tn5 transposase library construction with a signal-to-noise ratio above 50%. CONCLUSIONS Tn5 transposase method improves the efficiency of DNA library construction and the results of subsequent sequence analysis, and is especially suitable for detecting histone modification in the DNA to provide a better technical option for epigenetic studies.
Chromatin Immunoprecipitation ; DNA ; Gene Library ; High-Throughput Nucleotide Sequencing ; Humans ; Reproducibility of Results ; Sequence Analysis, DNA

Desensitization and acute tolerance are terms used to describe the attenuation of receptor responsiveness by prolonged or intermittent exposure to an agonist. Unlike desensitization of G protein-coupled receptors (GPCRs), which is commonly explained by steric hindrance caused by the β-arrestins that are translocated to the activated receptors, molecular mechanisms involved in the acute tolerance of GPCRs remain unclear. Our studies with several GPCRs and related mutants showed that the acute tolerance of GPCRs could occur independently of agonist-induced β-arrestin translocation. A series of co-immunoprecipitation experiments revealed a correlation between receptor tolerance and interactions among receptors, β-arrestin2, and Gβγ. Gβγ displayed a stable interaction with receptors and β-arrestin2 in cells expressing GPCRs that were prone to undergo tolerance compared to the GPCRs that were resistant to acute tolerance. Strengthening the interaction between Gβγ and β-arrestin rendered the GPCRs to acquire the tendency of acute tolerance. Overall, stable interaction between the receptor and Gβγ complex is required for the formation of a complex with β-arrestin, and determines the potential of a particular GPCR to undergo acute tolerance. Rather than turning off the signal, β-arrestins seem to contribute on continuous signaling when they are in the context of complex with receptor and Gβγ.
Immunoprecipitation ; Receptors, Dopamine D3

Glanzmann's thrombasthenia is a rare autosomal recessive hemorrhagic disorder characterized by prolonged bleeding time, ad deficient or absent clot retraction in the presence of normal platelet count. The major underlying abnormality in this disease is grossly defective first-phase aggregation of platelet, which are unresponsive to ADP or other platelet agonists such as epinephrine, collagen, thrombin in any concentration. This disability is caused by a decrease or absence of the platelet membrans glycoprotein IIb-IIIa complex, a member of the integrin family of adhesive receptors involved in cell-cell and cell-matrix fibronectin, and vitronectin On the development of surface labeling technique, a variety of biochemical techniques such as radioimmunoassay, crossed immunoelectrophoresis and SDS-PAGE have been used to study the structure and the function of platelet membrane glycoproteins, and to detect the platelet functional defect. But all of these techniques demand a relatively large amount of homogeneous paletelet population that requires manipulation through isolation and washing procedures before analysis. In order to eliminaste such an intricate procedure, we have applied method for analyzing platelet surface components in whole blood using monoclonal antibody and flow cytometry to recognize the absence of severe reduction of platelet membrane glycoprotien llb-llla complex. Platelet analysis by flow cytometry is a successful alternative rapid diagnostic technique for Glanzmann's thrombasthenia patients as well as well as for carriers of this disease. Fow cytometry technique provides a sensitive tool for investigating platelet functional defects caused by altered expression or deficiency of platelet surface proteins.
Adenosine Diphosphate ; Adhesives ; Bleeding Time ; Blood Platelets* ; Clot Retraction ; Collagen ; Electrophoresis, Polyacrylamide Gel ; Epinephrine ; Fibronectins ; Flow Cytometry* ; Glycoproteins ; Hemorrhagic Disorders ; Humans ; Immunoelectrophoresis, Two-Dimensional ; Membrane Glycoproteins* ; Membrane Proteins ; Membranes* ; Platelet Count ; Platelet Membrane Glycoproteins ; Radioimmunoassay ; Thrombasthenia* ; Thrombin ; Vitronectin

BACKGROUND: Tumor necrosis factor alpha (TNF-alpha) is a pleiotropic cytokine fulfilling a broad variety of immunoregulatory functions. Monocytes and macrophages play a pivotal role in inflammation and immune regulation. NF-kappaB and HIF-1 are known to increase expression of the TNF-alpha gene in a separate way. METHODS: Human monocytic leukemia, U937 cells, were transfected using the standard electroporation method for intracellular expression of NF-kappaB and HIF-1. We performed analysis using the mammalian two-hybrid assay and co-immunoprecipitation assay for detection of protein interaction of both proteins. In addition, chromatin immunoprecipitation analysis was performed for examination of NF-kappaB and HIF-1 binding on the TNF-alpha gene promoter. RESULTS: Here we show that NF-kappaB and HIF-1 cooperatively induced an increase in expression of the TNF-alpha gene dependent on promoter activity by the direct protein interaction of these two transcription factors. Hypoxia signaling induced marked enhancement of the transactivation of TNF-alpha promoter by HIF-1 and NF-kappaB. A tandem NF-kappaB/HIF-1 binding site was identified within the TNF-alpha promoter, which acted as a strong enhancer element. Physical association of the Rel domain of NF-kappaB and the N-TD domain of HIF-1 was required. Hypoxia treatment also resulted in a significant increase in the protein interaction of NF-kappaB and HIF-1 in vivo. Both transcription factors were recruited on the chromatin TNF-alpha promoter dependent on hypoxia stimuli. CONCLUSION: The results of this study indicate that a variety of extracellular signals for activation of TNF-alpha gene expression might converge on the transcriptional regulation through the NF-kappaB/HIF-1 signaling pathway.
Anoxia ; Binding Sites ; Chromatin ; Chromatin Immunoprecipitation ; Electroporation ; Enhancer Elements, Genetic ; Gene Expression ; Humans ; Immunoprecipitation ; Inflammation ; Leukemia ; Macrophages ; Monocytes ; NF-kappa B ; Proteins ; Transcription Factors ; Transcriptional Activation ; Tumor Necrosis Factor-alpha ; Two-Hybrid System Techniques ; U937 Cells