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1.
Nat Immunol ; 18(10): 1104-1116, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28825701

ABSTRACT

Cross-regulation of Toll-like receptor (TLR) responses by cytokines is essential for effective host defense, avoidance of toxicity and homeostasis, but the underlying mechanisms are not well understood. Our comprehensive epigenomics approach to the analysis of human macrophages showed that the proinflammatory cytokines TNF and type I interferons induced transcriptional cascades that altered chromatin states to broadly reprogram responses induced by TLR4. TNF tolerized genes encoding inflammatory molecules to prevent toxicity while preserving the induction of genes encoding antiviral and metabolic molecules. Type I interferons potentiated the inflammatory function of TNF by priming chromatin to prevent the silencing of target genes of the transcription factor NF-κB that encode inflammatory molecules. The priming of chromatin enabled robust transcriptional responses to weak upstream signals. Similar chromatin regulation occurred in human diseases. Our findings reveal that signaling crosstalk between interferons and TNF is integrated at the level of chromatin to reprogram inflammatory responses, and identify previously unknown functions and mechanisms of action of these cytokines.


Subject(s)
Epigenesis, Genetic , Inflammation/etiology , Inflammation/metabolism , Interferon Type I/metabolism , Macrophages/immunology , Macrophages/metabolism , Tumor Necrosis Factor-alpha/metabolism , Binding Sites , Chromatin Assembly and Disassembly , Chromatin Immunoprecipitation , Cluster Analysis , Computational Biology/methods , Cytokines/genetics , Cytokines/metabolism , Epigenomics/methods , Gene Expression Profiling , Gene Expression Regulation , High-Throughput Nucleotide Sequencing , Humans , Lipopolysaccharides/immunology , Lupus Erythematosus, Systemic/genetics , Lupus Erythematosus, Systemic/immunology , Lupus Erythematosus, Systemic/metabolism , Monocytes/immunology , Monocytes/metabolism , Nucleotide Motifs , Promoter Regions, Genetic , Protein Binding , Protein Transport , Signal Transduction , Toll-Like Receptor 4/metabolism , Transcription Factors/metabolism
2.
Immunity ; 47(2): 235-250.e4, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28813657

ABSTRACT

Mechanisms by which interferon (IFN)-γ activates genes to promote macrophage activation are well studied, but little is known about mechanisms and functions of IFN-γ-mediated gene repression. We used an integrated transcriptomic and epigenomic approach to analyze chromatin accessibility, histone modifications, transcription-factor binding, and gene expression in IFN-γ-primed human macrophages. IFN-γ suppressed basal expression of genes corresponding to an "M2"-like homeostatic and reparative phenotype. IFN-γ repressed genes by suppressing the function of enhancers enriched for binding by transcription factor MAF. Mechanistically, IFN-γ disassembled a subset of enhancers by inducing coordinate suppression of binding by MAF, lineage-determining transcription factors, and chromatin accessibility. Genes associated with MAF-binding enhancers were suppressed in macrophages isolated from rheumatoid-arthritis patients, revealing a disease-associated signature of IFN-γ-mediated repression. These results identify enhancer inactivation and disassembly as a mechanism of IFN-γ-mediated gene repression and reveal that MAF regulates the macrophage enhancer landscape and is suppressed by IFN-γ to augment macrophage activation.


Subject(s)
Arthritis, Rheumatoid/immunology , Chromatin Assembly and Disassembly , Interferon-gamma/metabolism , Macrophages/immunology , Proto-Oncogene Proteins c-maf/metabolism , Cell Differentiation , Cell Lineage , Cells, Cultured , Cytokines/metabolism , Enhancer Elements, Genetic/genetics , Gene Expression Regulation , Histones/metabolism , Humans , Protein Binding , Proto-Oncogene Proteins c-maf/genetics , Transcriptome
3.
Brief Bioinform ; 24(2)2023 03 19.
Article in English | MEDLINE | ID: mdl-36681937

ABSTRACT

Single-cell RNA-seq enabled in-depth study on tissue micro-environment and immune-profiling, where a crucial step is to annotate cell identity. Immune cells play key roles in many diseases, whereas their activities are hard to track due to their diverse and highly variable nature. Existing cell-type identifiers had limited performance for this purpose. We present HiCAT, a hierarchical, marker-based cell-type identifier utilising gene set analysis for statistical scoring for given markers. It features successive identification of major-type, minor-type and subsets utilising subset markers structured in a three-level taxonomy tree. Comparison with manual annotation and pairwise match test showed HiCAT outperforms others in major- and minor-type identification. For subsets, we qualitatively evaluated the marker expression profile demonstrating that HiCAT provide the clearest immune-cell landscape. HiCAT was also used for immune-cell profiling in ulcerative colitis and discovered distinct features of the disease in macrophage and T-cell subsets that could not be identified previously.


Subject(s)
Gene Expression Profiling , Macrophages , RNA
4.
Am J Pathol ; 193(1): 84-102, 2023 01.
Article in English | MEDLINE | ID: mdl-36464512

ABSTRACT

Molecular-level analyses of breast carcinogenesis benefit from vivo disease models. Estrogen receptor 1 (Esr1) and cytochrome P450 family 19 subfamily A member 1 (CYP19A1) overexpression targeted to mammary epithelial cells in genetically engineered mouse models induces largely similar rates of proliferative mammary disease in prereproductive senescent mice. Herein, with natural reproductive senescence, Esr1 overexpression compared with CYP19A1 overexpression resulted in significantly higher rates of preneoplasia and cancer. Before reproductive senescence, Esr1, but not CYP19A1, overexpressing mice are tamoxifen resistant. However, during reproductive senescence, Esr1 mice exhibited responsiveness. Both Esr1 and CYP19A1 are responsive to letrozole before and after reproductive senescence. Gene Set Enrichment Analyses of RNA-sequencing data sets showed that higher disease rates in Esr1 mice were accompanied by significantly higher expression of cell proliferation genes, including members of prognostic platforms for women with early-stage hormone receptor-positive disease. Tamoxifen and letrozole exposure induced down-regulation of these genes and resolved differences between the two models. Both Esr1 and CYP19A1 overexpression induced abnormal developmental patterns of pregnancy-like gene expression. This resolved with progression through reproductive senescence in CYP19A1 mice, but was more persistent in Esr1 mice, resolving only with tamoxifen and letrozole exposure. In summary, genetically engineered mouse models of Esr1 and CYP19A1 overexpression revealed a diversion of disease processes resulting from the two distinct molecular pathophysiological mammary gland-targeted intrusions into estrogen signaling during reproductive senescence.


Subject(s)
Aromatase , Epithelial Cells , Estrogen Receptor alpha , Mammary Glands, Animal , Animals , Female , Mice , Pregnancy , Epithelial Cells/metabolism , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Estrogens , Letrozole , Tamoxifen/pharmacology , Gene Expression , Mammary Glands, Animal/metabolism , Aromatase/genetics , Aromatase/metabolism
5.
Am J Pathol ; 193(1): 103-120, 2023 01.
Article in English | MEDLINE | ID: mdl-36464513

ABSTRACT

Age is a risk factor for human estrogen receptor-positive breast cancer, with highest prevalence following menopause. While transcriptome risk profiling is available for human breast cancers, it is not yet developed for prognostication for primary or secondary breast cancer development utilizing at-risk breast tissue. Both estrogen receptor α (ER) and aromatase overexpression have been linked to human breast cancer. Herein, conditional genetically engineered mouse models of estrogen receptor 1 (Esr1) and cytochrome P450 family 19 subfamily A member 1 (CYP19A1) were used to show that induction of Esr1 overexpression just before or with reproductive senescence and maintained through age 30 months resulted in significantly higher prevalence of estrogen receptor-positive adenocarcinomas than CYP19A1 overexpression. All adenocarcinomas tested showed high percentages of ER+ cells. Mammary cancer development was preceded by a persistent proliferative transcriptome risk signature initiated within 1 week of transgene induction that showed parallels to the Prosigna/Prediction Analysis of Microarray 50 human prognostic signature for early-stage human ER+ breast cancer. CYP19A1 mice also developed ER+ mammary cancers, but histology was more divided between adenocarcinoma and adenosquamous, with one ER- adenocarcinoma. Results demonstrate that, like humans, generation of ER+ adenocarcinoma in mice was facilitated by aging mice past the age of reproductive senescence. Esr1 overexpression was associated with a proliferative estrogen pathway-linked signature that preceded appearance of ER+ mammary adenocarcinomas.


Subject(s)
Adenocarcinoma , Breast Neoplasms , Mammary Glands, Animal , Animals , Female , Mice , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Aging/genetics , Aging/metabolism , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Mammary Glands, Animal/metabolism , Mammary Glands, Animal/pathology , Gene Expression , Aromatase/genetics , Aromatase/metabolism , Reproduction/genetics , Reproduction/physiology
6.
BMC Cancer ; 21(1): 931, 2021 Aug 18.
Article in English | MEDLINE | ID: mdl-34407787

ABSTRACT

BACKGROUND: The mechanisms of endocrine resistance are complex, and deregulation of several oncogenic signalling pathways has been proposed. We aimed to investigate the role of the EGFR and Src-mediated STAT3 signalling pathway in tamoxifen-resistant breast cancer cells. METHODS: The ER-positive luminal breast cancer cell lines, MCF-7 and T47D, were used. We have established an MCF-7-derived tamoxifen-resistant cell line (TamR) by long-term culture of MCF-7 cells with 4-hydroxytamoxifen. Cell viability was determined using an MTT assay, and protein expression levels were determined using western blot. Cell cycle and annexin V staining were analysed using flow cytometry. RESULTS: TamR cells showed decreased expression of estrogen receptor and increased expression of EGFR. TamR cells showed an acceleration of the G1 to S phase transition. The protein expression levels of phosphorylated Src, EGFR (Y845), and STAT3 was increased in TamR cells, while phosphorylated Akt was decreased. The expression of p-STAT3 was enhanced according to exposure time of tamoxifen in T47D cells, suggesting that activation of STAT3 can cause tamoxifen resistance in ER-positive breast cancer cells. Both dasatinib (Src inhibitor) and stattic (STAT3 inhibitor) inhibited cell proliferation and induced apoptosis in TamR cells. However, stattic showed a much stronger effect than dasatinib. Knockdown of STAT3 expression by siRNA had no effect on sensitivity to tamoxifen in MCF-7 cells, while that enhanced sensitivity to tamoxifen in TamR cells. There was not a significant synergistic effect of dasatinib and stattic on cell survival. TamR cells have low nuclear p21(Cip1) expression compared to MCF-7 cells and inhibition of STAT3 increased the expression of nuclear p21(Cip1) in TamR cells. CONCLUSIONS: The EGFR and Src-mediated STAT3 signalling pathway is activated in TamR cells, and inhibition of STAT3 may be a potential target in tamoxifen-resistant breast cancer. An increase in nuclear p21(Cip1) may be a key step in STAT3 inhibitor-induced cell death in TamR cells.


Subject(s)
Breast Neoplasms/drug therapy , Cyclic S-Oxides/pharmacology , Drug Resistance, Neoplasm/drug effects , Gene Expression Regulation, Neoplastic/drug effects , STAT3 Transcription Factor/antagonists & inhibitors , Tamoxifen/pharmacology , Antineoplastic Agents, Hormonal/pharmacology , Apoptosis , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Cycle , Cell Movement , Cell Proliferation , Female , Humans , Tumor Cells, Cultured
7.
Arch Toxicol ; 94(3): 887-909, 2020 03.
Article in English | MEDLINE | ID: mdl-32080758

ABSTRACT

Polyhexamethylene guanidine phosphate (PHMG-p) was used as a humidifier disinfectant in Korea. PHMG induced severe pulmonary fibrosis in Koreans. The objective of this study was to elucidate mechanism of pulmonary toxicity caused by PHMG-p in rats using multi-omics analysis. Wistar rats were intratracheally instilled with PHMG-p by single (1.5 mg/kg) administration or 4-week (0.1 mg/kg, 2 times/week) repeated administration. Histopathologic examination was performed with hematoxylin and eosin staining. Alveolar macrophage aggregation and granulomatous inflammation were observed in rats treated with single dose of PHMG-p. Pulmonary fibrosis, chronic inflammation, bronchiol-alveolar fibrosis, and metaplasia of squamous cell were observed in repeated dose group. Next generation sequencing (NGS) was performed for transcriptome profiling after mRNA isolation from bronchiol-alveoli. Bronchiol-alveoli proteomic profiling was performed using an Orbitrap Q-exactive mass spectrometer. Serum and urinary metabolites were determined using 1H-NMR. Among 418 differentially expressed genes (DEGs) and 67 differentially expressed proteins (DEPs), changes of 16 mRNA levels were significantly correlated with changes of their protein levels in both single and repeated dose groups. Remarkable biological processes represented by both DEGs and DEPs were defense response, inflammatory response, response to stress, and immune response. Arginase 1 (Arg1) and lipocalin 2 (Lcn2) were identified to be major regulators for PHMG-p-induced pulmonary toxicity based on merged analysis using DEGs and DEPs. In metabolomics study, 52 metabolites (VIP > 0.5) were determined in serum and urine of single and repeated-dose groups. Glutamate and choline were selected as major metabolites. They were found to be major factors affecting inflammatory response in association with DEGs and DEPs. Arg1 and Lcn2 were suggested to be major gene and protein related to pulmonary damage by PHMG-p while serum or urinary glutamate and choline were endogenous metabolites related to pulmonary damage by PHMG-p.


Subject(s)
Disinfectants/toxicity , Guanidines/toxicity , Lung Injury/chemically induced , Animals , Biomarkers/metabolism , Computational Biology , Epithelial Cells , Gene Expression Profiling , Humidifiers , Lung , Lung Injury/veterinary , Male , Metabolomics , Proteomics , Pulmonary Alveoli , Pulmonary Fibrosis , Rats , Rats, Wistar , Republic of Korea , Toxicity Tests , Transcriptome
8.
Nucleic Acids Res ; 46(9): e53, 2018 05 18.
Article in English | MEDLINE | ID: mdl-29420797

ABSTRACT

Octopus-toolkit is a stand-alone application for retrieving and processing large sets of next-generation sequencing (NGS) data with a single step. Octopus-toolkit is an automated set-up-and-analysis pipeline utilizing the Aspera, SRA Toolkit, FastQC, Trimmomatic, HISAT2, STAR, Samtools, and HOMER applications. All the applications are installed on the user's computer when the program starts. Upon the installation, it can automatically retrieve original files of various epigenomic and transcriptomic data sets, including ChIP-seq, ATAC-seq, DNase-seq, MeDIP-seq, MNase-seq and RNA-seq, from the gene expression omnibus data repository. The downloaded files can then be sequentially processed to generate BAM and BigWig files, which are used for advanced analyses and visualization. Currently, it can process NGS data from popular model genomes such as, human (Homo sapiens), mouse (Mus musculus), dog (Canis lupus familiaris), plant (Arabidopsis thaliana), zebrafish (Danio rerio), fruit fly (Drosophila melanogaster), worm (Caenorhabditis elegans), and budding yeast (Saccharomyces cerevisiae) genomes. With the processed files from Octopus-toolkit, the meta-analysis of various data sets, motif searches for DNA-binding proteins, and the identification of differentially expressed genes and/or protein-binding sites can be easily conducted with few commands by users. Overall, Octopus-toolkit facilitates the systematic and integrative analysis of available epigenomic and transcriptomic NGS big data.


Subject(s)
Epigenesis, Genetic , Gene Expression Profiling , High-Throughput Nucleotide Sequencing , Software , Animals , DNA-Binding Proteins/metabolism , Data Mining , Histones/metabolism , Mice , STAT5 Transcription Factor/metabolism , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Workflow
9.
Int J Mol Sci ; 21(17)2020 Aug 26.
Article in English | MEDLINE | ID: mdl-32858881

ABSTRACT

Forkhead box protein M1 (FOXM1) is a key transcription factor (TF) that regulates a common set of genes related to the cell cycle in various cell types. However, the mechanism by which FOXM1 controls the common gene set in different cellular contexts is unclear. In this study, a comprehensive meta-analysis of genome-wide FOXM1 binding sites in ECC-1, GM12878, K562, MCF-7, and SK-N-SH cell lines was conducted to predict FOXM1-driven gene regulation. Consistent with previous studies, different TF binding motifs were identified at FOXM1 binding sites, while the NFY binding motif was found at 81% of common FOXM1 binding sites in promoters of cell cycle-related genes. The results indicated that FOXM1 might control the gene set through interaction with the NFY proteins, while cell type-specific genes were predicted to be regulated by enhancers with FOXM1 and cell type-specific TFs. We also found that the high expression level of FOXM1 was significantly associated with poor prognosis in nine types of cancer. Overall, these results suggest that FOXM1 is predicted to function as a master regulator of the cell cycle through the interaction of NFY-family proteins, and therefore the inhibition of FOXM1 could be an attractive strategy for cancer therapy.


Subject(s)
Forkhead Box Protein M1/genetics , Forkhead Box Protein M1/metabolism , Gene Regulatory Networks , Neoplasms/genetics , Binding Sites , Cell Cycle , Cell Line, Tumor , Chromatin Immunoprecipitation Sequencing , Gene Expression Regulation, Neoplastic , Humans , K562 Cells , MCF-7 Cells , Neoplasms/metabolism , Prognosis , Up-Regulation , Whole Genome Sequencing
10.
Int J Cancer ; 145(6): 1585-1595, 2019 09 15.
Article in English | MEDLINE | ID: mdl-31026342

ABSTRACT

The microRNA-200 (miR-200) family plays a major role in specifying epithelial phenotype by preventing expression of the transcription repressors ZEB1 and ZEB2, which are well-known regulators of the epithelial-to-mesenchymal transition (EMT) in epithelial tumors including oral squamous cell carcinoma (OSCC). Here, we elucidated whether miR-200 family members control RNA-binding protein quaking (QKI), a newly identified tumor suppressor that is regulated during EMT. We predicted that miR-200a and miR-200b could recognize QKI 3'-UTR by analyzing TargetScan and The Cancer Genome Atlas head and neck squamous cell carcinoma (HNSCC) dataset. Forced expression of miR-200b/a/429 inhibited expression of ZEB1/2 and decreased cell migration in OSCC cell lines CAL27 and HSC3. QKI expression was also suppressed by miR-200 overexpression, and the 3'-UTR of QKI mRNA was directly targeted by miR-200 in luciferase reporter assays. Interestingly, shRNA-mediated knockdown of QKI led to pronounced EMT and protumor effects in both in vitro and in vivo studies of OSCC. Furthermore, high expression of QKI protein is associated with favorable prognosis in surgically resected HNSCC and lung adenocarcinoma. In conclusion, QKI increases during EMT and is targeted by miR-200; while, it suppresses EMT and tumorigenesis. We suggest that QKI and miR-200 form a negative feedback loop to maintain homeostatic responses to EMT-inducing signals.


Subject(s)
Carcinoma, Squamous Cell/pathology , Cell Proliferation/genetics , Epithelial-Mesenchymal Transition/genetics , MicroRNAs/genetics , Mouth Neoplasms/pathology , RNA-Binding Proteins/genetics , 3' Untranslated Regions , Animals , Carcinoma, Squamous Cell/genetics , Cell Line, Tumor , Female , Gene Expression , Gene Knockdown Techniques , Heterografts , Humans , Inflammation Mediators/metabolism , Mice , Mice, Inbred BALB C , Mouth Neoplasms/genetics , Prognosis
11.
Mamm Genome ; 30(9-10): 289-300, 2019 10.
Article in English | MEDLINE | ID: mdl-31414176

ABSTRACT

Naturally occurring diseases in dogs provide an important animal model for studying human disease including cancer, heart disease, and autoimmune disorders. Transposable elements (TEs) make up ~ 31% of the dog (Canis lupus familiaris) genome and are one of main drivers to cause genomic variations and alter gene expression patterns of the host genes, which could result in genetic diseases. To detect structural variations (SVs), we conducted whole-genome sequencing of three different breeds, including Maltese, Poodle, and Yorkshire Terrier. Genomic SVs were detected and visualized using BreakDancer program. We identified a total of 2328 deletion SV events in the three breeds compared with the dog reference genome of Boxer. The majority of the genetic variants were found to be TE insertion polymorphism (1229) and the others were TE-mediated deletion (489), non-TE-mediated deletion (542), simple repeat-mediated deletion (32), and other indel (36). Among the TE insertion polymorphism, 286 elements were full-length LINE-1s (L1s). In addition, the 49 SV candidates located in the genic regions were experimentally verified and their polymorphic rates within each breed were examined using PCR assay. Polymorphism analysis of the genomic variants revealed that some of the variants exist polymorphic in the three dog breeds, suggesting that their SV events recently occurred in the dog genome. The findings suggest that TEs have contributed to the genomic variations among the three dog breeds of Maltese, Poodle, and Yorkshire Terrier. In addition, the polymorphic events between the dog breeds indicate that TEs were recently retrotransposed in the dog genome.


Subject(s)
Dogs/genetics , Genome , Animals , Breeding , DNA Transposable Elements , Dogs/classification , Dogs/physiology , Genetic Variation , INDEL Mutation
12.
Hepatology ; 67(4): 1360-1377, 2018 04.
Article in English | MEDLINE | ID: mdl-29059470

ABSTRACT

An accurate tool enabling early diagnosis of hepatocellular carcinoma (HCC) is clinically important, given that early detection of HCC markedly improves survival. We aimed to investigate the molecular markers underlying early progression of HCC that can be detected in precancerous lesions. We designed a gene selection strategy to identify potential driver genes by integrative analysis of transcriptome and clinicopathological data of human multistage HCC tissues, including precancerous lesions, low- and high-grade dysplastic nodules. The gene selection process was guided by detecting the selected molecules in both HCC and precancerous lesion. Using various computational approaches, we selected 10 gene elements as a candidate and, through immunohistochemical staining, showed that barrier to autointegration factor 1 (BANF1), procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3 (PLOD3), and splicing factor 3b subunit 4 (SF3B4) are HCC decision markers with superior capability to diagnose early-stage HCC in a large cohort of HCC patients, as compared to the currently popular trio of HCC diagnostic markers: glypican 3, glutamine synthetase, and heat-shock protein 70. Targeted inactivation of BANF1, PLOD3, and SF3B4 inhibits in vitro and in vivo liver tumorigenesis by selectively modulating epithelial-mesenchymal transition and cell-cycle proteins. Treatment of nanoparticles containing small-interfering RNAs of the three genes suppressed liver tumor incidence as well as tumor growth rates in a spontaneous mouse HCC model. We also demonstrated that SF3B4 overexpression triggers SF3b complex to splice tumor suppressor KLF4 transcript to nonfunctional skipped exon transcripts. This contributes to malignant transformation and growth of hepatocyte through transcriptional inactivation of p27Kip1 and simultaneously activation of Slug genes. CONCLUSION: The findings suggest molecular markers of BANF1, PLOD3, and SF3B4 indicating early-stage HCC in precancerous lesion, and also suggest drivers for understanding the development of hepatocarcinogenesis. (Hepatology 2018;67:1360-1377).


Subject(s)
Carcinoma, Hepatocellular/metabolism , DNA-Binding Proteins/metabolism , Liver Neoplasms/metabolism , Nuclear Proteins/metabolism , Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase/metabolism , RNA Splicing Factors/metabolism , Animals , Biomarkers, Tumor/metabolism , Blotting, Western , Carcinogenesis/metabolism , Carcinoma, Hepatocellular/pathology , Humans , Immunohistochemistry , Kruppel-Like Factor 4 , Liver/metabolism , Liver/pathology , Liver Neoplasms/pathology , Mice , Rats , Tissue Array Analysis/methods
13.
J Biol Chem ; 292(41): 17144-17155, 2017 10 13.
Article in English | MEDLINE | ID: mdl-28784663

ABSTRACT

Cumulative evidence suggests that non-proteolytic functions of the proteasome are involved in transcriptional regulation, mRNA export, and ubiquitin-dependent histone modification and thereby modulate the intracellular levels of regulatory proteins implicated in controlling key cellular functions. To date, the non-proteolytic roles of the proteasome have been mainly investigated in euchromatin; their effects on heterochromatin are largely unknown. Here, using fission yeast as a model, we randomly mutagenized the subunits of the 19S proteasome subcomplex and sought to uncover a direct role of the proteasome in heterochromatin regulation. We identified a mutant allele, rpt4-1, that disrupts a non-proteolytic function of the proteasome, also known as a non-proteolytic allele. Experiments performed using rpt4-1 cells revealed that the proteasome is involved in the regulation of heterochromatin spreading to prevent its uncontrolled invasion into neighboring euchromatin regions. Intriguingly, the phenotype of the non-proteolytic rpt4-1 mutant resembled that of epe1Δ cells, which lack the Epe1 protein that counteracts heterochromatin spreading. Both mutants exhibited variegated gene-silencing phenotypes across yeast colonies, spreading of heterochromatin, bypassing of the requirement for RNAi in heterochromatin formation at the outer repeat region (otr), and up-regulation of RNA polymerase II. Further analysis revealed Mst2, another factor that antagonizes heterochromatin spreading, may function redundantly with Rpt4. These observations suggest that the 19S proteasome may be involved in modulating the activities of Epe1 and Mst2. In conclusion, our findings indicate that the proteasome appears to have a heterochromatin-regulating function that is independent of its canonical function in proteolysis.


Subject(s)
Heterochromatin/enzymology , Proteasome Endopeptidase Complex/metabolism , Schizosaccharomyces/enzymology , Heterochromatin/genetics , Histone Acetyltransferases/genetics , Histone Acetyltransferases/metabolism , Mutation , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Proteasome Endopeptidase Complex/genetics , RNA Polymerase II/genetics , RNA Polymerase II/metabolism , Schizosaccharomyces/genetics , Schizosaccharomyces pombe Proteins/genetics , Schizosaccharomyces pombe Proteins/metabolism
14.
BMC Genomics ; 19(1): 653, 2018 Sep 04.
Article in English | MEDLINE | ID: mdl-30180798

ABSTRACT

BACKGROUND: The challenges when developing a good de novo transcriptome assembler include how to deal with read errors and sequence repeats. Almost all de novo assemblers utilize a de Bruijn graph, with which complexity grows linearly with data size while suffering from errors and repeats. Although one can correct the errors by inspecting the topological structure of the graph, this is not an easy task when there are too many branches. Two research directions are to improve either the graph reliability or the path search precision, and in this study, we focused on the former. RESULTS: We present TraRECo, a greedy approach to de novo assembly employing error-aware graph construction. In the proposed approach, we built contigs by direct read alignment within a distance margin and performed a junction search to construct splicing graphs. While doing so, a contig of length l was represented by a 4 × l matrix (called a consensus matrix), in which each element was the base count of the aligned reads so far. A representative sequence was obtained by taking the majority in each column of the consensus matrix to be used for further read alignment. Once the splicing graphs had been obtained, we used IsoLasso to find paths with a noticeable read depth. The experiments using real and simulated reads show that the method provided considerable improvement in sensitivity and moderately better performance when comparing sensitivity and precision. This was achieved by the error-aware graph construction using the consensus matrix, with which the reads having errors were made usable for the graph construction (otherwise, they might have been eventually discarded). This improved the quality of the coverage depth information used in the subsequent path search step and finally the reliability of the graph. CONCLUSIONS: De novo assembly is mainly used to explore undiscovered isoforms and must be able to represent as many reads as possible in an efficient way. In this sense, TraRECo provides us with a potential alternative for improving graph reliability even though the computational burden is much higher than the single k-mer in the de Bruijn graph approach.


Subject(s)
Computational Biology , Embryonic Stem Cells/metabolism , Sequence Analysis, DNA/methods , Software , Transcriptome , Animals , Embryonic Stem Cells/cytology , High-Throughput Nucleotide Sequencing , Humans , Mice
15.
Int J Syst Evol Microbiol ; 68(3): 924-929, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29458494

ABSTRACT

Strain M1-21T is a Gram-stain-negative, strictly aerobic and short-rod-shaped bacterium, motile by means of a single polar flagellum; it was isolated from freshwater sediment in Korea. It grew at 10-40 °C (optimum 25 °C), pH 6.0-8.0 (optimum pH 7.0) and with 0-0.75 % (w/v) NaCl (optimal growth occurred in the absence of NaCl) on R2A agar, and it accumulated poly-ß-hydroxybutyrate granules inside the cells. According to 16S rRNA gene sequence analysis, strain M1-21T showed highest sequence similarity with Uliginosibacterium gangwonense (94.7 %) and Uliginosibacterium paludis (94.4 %). Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain M1-21T belongs to the genus Uliginosibacterium. The DNA G+C content of strain M1-21T was 61.9 mol%. The predominant respiratory quinone was ubiquinone-8. The major fatty acids (>10 % of the total) were C16 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Strain M1-21T showed distinct phenotypic characteristics that differentiated it from species of the genus Uliginosibacterium. Based on these results, strain M1-21T represents a novel species of the genus Uliginosibacterium, for which the name Uliginosibacterium sediminicola sp. nov. is proposed. The type strain is M1-21T (=KACC 19271T=JCM 32000T).


Subject(s)
Fresh Water/microbiology , Geologic Sediments/microbiology , Phylogeny , Rhodocyclaceae/classification , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Hydroxybutyrates/chemistry , Phospholipids/chemistry , Polyesters/chemistry , RNA, Ribosomal, 16S/genetics , Republic of Korea , Rhodocyclaceae/genetics , Rhodocyclaceae/isolation & purification , Sequence Analysis, DNA , Ubiquinone/chemistry
16.
Int J Syst Evol Microbiol ; 68(8): 2478-2484, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29923816

ABSTRACT

A bacterial strain, designated D13T, was isolated from sandy soil near a stream in Sinan-gun, Republic of Korea. Cells were Gram-stain-negative, aerobic, non-motile and flexible rod-shaped. Growth occurred at 15-35 °C (optimum 30 °C) and pH 6.5-8.0 (pH 7.0). NaCl was not obligatory for growth but could be tolerated at up to 0.5 % (w/v) NaCl. The DNA G+C content of the genomic DNA of strain D13T was 57.7 mol% and a phylogenetic analysis of the 16S rRNA gene sequence revealed that strain D13T formed a distinct evolutionary lineage within the family Rhodanobacteraceae of the order Lysobacterales. Strain D13T showed highest 16S rRNA sequence similarity to Lysobacter hankyongensis KTCe-2T (92.7 %), followed by Luteimonas cucumeris Y4T (92.7 %), Dyella japonica XD53T (92.6 %) and Aquimonas voraii GPTSA 20T (92.5 %). The major cellular fatty acids (>10 % of the total) were iso-C16 : 0, iso-C15 : 0 and summed feature 9 (iso-C17 : 1ω9с and/or C16 : 0 10-methyl). The respiratory quinone was ubiquinone-8 and the major polar lipids of the isolate consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylmonomethylethanolamine. Based on polyphasic analysis, strain D13T could be differentiated from other genera in the family Rhodanobacteraceae, which suggests that strain D13T represents a novel species of a new genus in the family Rhodanobacteraceae, for which the name Ahniella affigens gen. nov., sp. nov. is proposed. The type strain is D13T (=KACC 19270T=JCM 31634T).


Subject(s)
Gammaproteobacteria/classification , Phylogeny , Rivers , Soil Microbiology , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Gammaproteobacteria/genetics , Gammaproteobacteria/isolation & purification , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Republic of Korea , Sequence Analysis, DNA , Ubiquinone/chemistry
17.
Int J Syst Evol Microbiol ; 68(9): 3040-3046, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30067175

ABSTRACT

Two strains of Gram-stain-positive, endospore-forming, motile by means of peritrichous flagella, aerobic or facultative anaerobic, and rod-shaped bacteria that were designated ON8T and ON6T were isolated from soil collected from a mountain wetland in Gwang-ju, Republic of Korea. The isolates were catalase-positive and oxidase-negative. Cells of ON8T and ON6T grew at 15-35 °C (optimal 30 °C) and 15-40 °C (optimal 30 °C), respectively. The major menaquinone was MK-7 and the major cellular fatty acids (>10 % of the total) were anteiso-C15 : 0, iso-C15 : 0, C14 : 0 and C16 : 0. The predominant polar lipids were diphosphatidylglycerol, aminophospholipid and phospholipid. Meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The DNA G+C contents of strains ON8T and ON6T were 50.6 and 53.5 mol%, respectively, and the 16S rRNA gene sequence analysis showed that the nearest phylogenetic neighbour of both strains was Gorillibacterium massiliense G5T (93.9 %), followed by the members of the genus Paenibacillus in the family Paenibacillaceae. The DNA-DNA hybridization relatedness value between ON8T and ON6T was 44.1 %, which indicated that they represented distinct species. Based on polyphasic characteristics, a novel genus is proposed with the name Paludirhabdus gen. nov., which consists of two species, Paludirhabdus telluriireducens sp. nov. (the type species; type strain ON8T=KACC 19267T=JCM 31958T) and Paludirhabdus pumila sp. nov. (type strain ON6T=KACC 19266T=JCM 31957T).


Subject(s)
Bacillales/classification , Phylogeny , Soil Microbiology , Wetlands , Bacillales/genetics , Bacillales/isolation & purification , Bacterial Typing Techniques , Base Composition , Cell Wall/chemistry , DNA, Bacterial/genetics , Diaminopimelic Acid/chemistry , Fatty Acids/chemistry , Nucleic Acid Hybridization , Peptidoglycan/chemistry , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Republic of Korea , Sequence Analysis, DNA , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistry
18.
Int J Syst Evol Microbiol ; 68(3): 782-787, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29458474

ABSTRACT

An aerobic, Gram-negative, motile by means of a single polar flagellum, and ovoid-shaped bacterium, designated D3T, was isolated from shallow stream sediments in Sinan-gun, South Korea. Growth occurred at 15-40 °C (optimum 35 °C), at pH 7.0-8.0 (optimum pH 7.0), and at an optimum NaCl concentration of 0.5 % (w/v). The major cellular fatty acids (>7 % of the total) were C16 : 0, C18 : 0 2-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The predominant quinone was ubiquinone-10, and the G+C content of the genomic DNA of strain D3T was 73.1 mol%. The major polyamine was spermidine. The major polar lipids of the isolate were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain D3T clustered with Roseomonas aquatica TR53T within the genus Roseomonas. The 16S rRNA gene sequence of strain D3T showed the highest sequence similarity to R. aquatica TR53T (95.9 %), followed by Roseomonas rosea 173-96T (95.7 %) and Roseomonas aerilata 5420S-30T (95.0 %). Based on the phenotypic, phylogenetic and chemotaxonomic characterization, strain D3T represents a novel species of the genus Roseomonas, for which the name Roseomonas fluminis sp. nov. is proposed. The type strain is D3T (=KACC 19269T=JCM 31968T).


Subject(s)
Geologic Sediments/microbiology , Methylobacteriaceae/classification , Phylogeny , Rivers/microbiology , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Methylobacteriaceae/genetics , Methylobacteriaceae/isolation & purification , Nucleic Acid Hybridization , Phosphatidylglycerols/chemistry , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Republic of Korea , Sequence Analysis, DNA , Ubiquinone/chemistry
19.
Nucleic Acids Res ; 44(3): 1052-63, 2016 Feb 18.
Article in English | MEDLINE | ID: mdl-26446995

ABSTRACT

Signal Transducers and Activators of Transcription (STATs) are principal transcription factors downstream of cytokine receptors. Although STAT5A is expressed in most tissues it remains to be understood why its premier, non-redundant functions are restricted to prolactin-induced mammary gland development and function. We report that the ubiquitously expressed Stat5a/b locus is subject to additional lineage-specific transcriptional control in mammary epithelium. Genome-wide surveys of epigenetic status and transcription factor occupancy uncovered a putative mammary-specific enhancer within the intergenic sequences separating the two Stat5 genes. This region exhibited several hallmarks of genomic enhancers, including DNaseI hypersensitivity, H3K27 acetylation and binding by GR, NFIB, ELF5 and MED1. Mammary-specific STAT5 binding was obtained at two canonical STAT5 binding motifs. CRISPR/Cas9-mediated genome editing was used to delete these sites in mice and determine their biological function. Mutant animals exhibited an 80% reduction of Stat5 levels in mammary epithelium and a concomitant reduction of STAT5-dependent gene expression. Transcriptome analysis identified a class of mammary-restricted genes that was particularly dependent on high STAT5 levels as a result of the intergenic enhancer. Taken together, the mammary-specific enhancer enables a positive feedback circuit that contributes to the remarkable abundance of STAT5 and, in turn, to the efficacy of STAT5-dependent mammary physiology.


Subject(s)
Enhancer Elements, Genetic , Mammary Glands, Human/metabolism , STAT5 Transcription Factor/physiology , Animals , Base Sequence , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , DNA , Female , Humans , Mice , Molecular Sequence Data , STAT5 Transcription Factor/genetics
20.
Int J Mol Sci ; 19(5)2018 May 14.
Article in English | MEDLINE | ID: mdl-29757984

ABSTRACT

BRCA1 is a multifunctional tumor suppressor involved in several essential cellular processes. Although many of these functions are driven by or related to its transcriptional/epigenetic regulator activity, there has been no genome-wide study to reveal the transcriptional/epigenetic targets of BRCA1. Therefore, we conducted a comprehensive analysis of genomics/transcriptomics data to identify novel BRCA1 target genes. We first analyzed ENCODE data with BRCA1 chromatin immunoprecipitation (ChIP)-sequencing results and identified a set of genes with a promoter occupied by BRCA1. We collected 3085 loci with a BRCA1 ChIP signal from four cell lines and calculated the distance between the loci and the nearest gene transcription start site (TSS). Overall, 66.5% of the BRCA1-bound loci fell into a 2-kb region around the TSS, suggesting a role in transcriptional regulation. We selected 45 candidate genes based on gene expression correlation data, obtained from two GEO (Gene Expression Omnibus) datasets and TCGA data of human breast cancer, compared to BRCA1 expression levels. Among them, we further tested three genes (MEIS2, CKS1B and FADD) and verified FADD as a novel direct target of BRCA1 by ChIP, RT-PCR, and a luciferase reporter assay. Collectively, our data demonstrate genome-wide transcriptional regulation by BRCA1 and suggest target genes as biomarker candidates for BRCA1-associated breast cancer.


Subject(s)
BRCA1 Protein/metabolism , Computational Biology , Databases, Genetic , Gene Expression Regulation, Neoplastic , Carrier Proteins/metabolism , Cell Survival , Chromatin Immunoprecipitation , Computational Biology/methods , Gene Knockdown Techniques , Humans , Promoter Regions, Genetic , Protein Binding , Signal Transduction , Transcription Factors , Transcription Initiation Site
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