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1.
Plant Physiol ; 184(4): 1744-1761, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33020252

RESUMO

C13-apocarotenoids (norisoprenoids) are carotenoid-derived oxidation products that perform important physiological functions in plants. Although their biosynthetic pathways have been extensively studied, their metabolism including glycosylation remains poorly understood. Candidate uridine-diphosphate glycosyltransferase genes (UGTs) were selected based on their high transcript abundance in comparison with other UGTs in vegetative tissues of Nicotiana benthamiana and peppermint (Mentha × piperita), as these tissues are rich sources of apocarotenoid glucosides. Hydroxylated C13-apocarotenol substrates were produced by P450-catalyzed biotransformation and microbial/plant enzyme systems were established for the synthesis of glycosides. Natural substrates were identified by physiological aglycone libraries prepared from isolated plant glycosides. In total, we identified six UGTs that catalyze the glucosylation of C13-apocarotenols, where Glc is bound either to the cyclohexene ring or the butane side chain. MpUGT86C10 is a superior novel enzyme that catalyzes the glucosylation of allelopathic 3-hydroxy-α-damascone, 3-oxo-α-ionol, 3-oxo-7,8-dihydro-α-ionol (Blumenol C), and 3-hydroxy-7,8-dihydro-ß-ionol, whereas a germination test demonstrated the higher phytotoxic potential of a norisoprenoid glucoside in comparison to its aglycone. Glycosylation of C13-apocarotenoids has several functions in plants, including increased allelopathic activity of the aglycone, facilitating exudation by roots and allowing symbiosis with arbuscular mycorrhizal fungi. The results enable in-depth analysis of the roles of glycosylated norisoprenoid allelochemicals, the physiological functions of apocarotenoids during arbuscular mycorrhizal colonization, and the associated maintenance of carotenoid homeostasis.

2.
Plant J ; 100(1): 20-37, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31124249

RESUMO

Enzyme promiscuity, a common property of many uridine diphosphate sugar-dependent glycosyltransferases (UGTs) that convert small molecules, significantly hinders the identification of natural substrates and therefore the characterization of the physiological role of enzymes. In this paper we present a simple but effective strategy to identify endogenous substrates of plant UGTs using LC-MS-guided targeted glycoside analysis of transgenic plants. We successfully identified natural substrates of two promiscuous Nicotiana benthamiana UGTs (NbUGT73A24 and NbUGT73A25), orthologues of pathogen-induced tobacco UGT (TOGT) from Nicotiana tabacum, which is involved in the hypersensitive reaction. While in N. tabacum, TOGT glucosylated scopoletin after treatment with salicylate, fungal elicitors and the tobacco mosaic virus, NbUGT73A24 and NbUGT73A25 produced glucosides of phytoalexin N-feruloyl tyramine, which may strengthen cell walls to prevent the intrusion of pathogens, and flavonols after agroinfiltration of the corresponding genes in N. benthamiana. Enzymatic glucosylation of fractions of a physiological aglycone library confirmed the biological substrates of UGTs. In addition, overexpression of both genes in N. benthamiana produced clear lesions on the leaves and led to a significantly reduced content of pathogen-induced plant metabolites such as phenylalanine and tryptophan. Our results revealed some additional biological functions of TOGT enzymes and indicated a multifunctional role of UGTs in plant resistance.


Assuntos
Ácidos Cumáricos/metabolismo , Glucose/metabolismo , Glicosiltransferases/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Sesquiterpenos/metabolismo , Tabaco/genética , Tiramina/análogos & derivados , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Glicosídeos/metabolismo , Glicosilação , Glicosiltransferases/metabolismo , Doenças das Plantas/virologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/virologia , Proteínas de Plantas/metabolismo , Especificidade por Substrato , Tabaco/metabolismo , Tabaco/virologia , Vírus do Mosaico do Tabaco/fisiologia , Tiramina/metabolismo
3.
Cell Mol Biol Lett ; 24: 13, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30805015

RESUMO

Background: Hepatitis B virus (HBV) infection is acknowledged as the main cause of hepatocellular carcinoma (HCC). Moreover, previous studies have revealed that microRNAs (miRNAs) widely participate in regulation of various cellular processes, such as viral replication. Hence, the purpose of this study was to investigate the roles of aquaporin 5 (AQP5) and miR-325-3p in the proliferation and apoptosis of HBV-related HCC cells. Methods: AQP5 and miR-325-3p expression in both normal and HBV-HCC tissues or cells (both Huh7-1.3 and HepG2.2.15) was detected using qRT-PCR. AQP5 expression was knocked down in HBV-related Huh7-1.3 and HepG2.2.15 cells using small interfering RNA (siRNA) technology. Down-regulation was confirmed using real-time PCR and Western blot analysis. Effects of AQP5 down-regulation on the proliferation and apoptosis were assessed. Dual luciferase reporter gene assay, Western blot and qRT-PCR were employed to evaluate the effect of miR-325-3p on the luciferase activity and expression of AQP5. Moreover, miR-325-3p mimic-induced changes in cellular proliferation and apoptosis were detected through CCK-8 assay, BrdU assay, flow cytometry analysis and ELISA. Results: In this study, the expression of AQP5 was up-regulated in human HBV-HCC tissue, Huh7-1.3 and HepG2.2.15 cells. Knockdown of AQP5 significantly inhibited the proliferation and promoted apoptosis of HBV-HCC cells. Next, miR-325-3p was obviously down-regulated in HBV-HCC. In concordance with this, MiR-325-3p directly targeted AQP5, and reduced both mRNA and protein levels of AQP5, which promoted cell proliferation and suppressed cell apoptosis in HCC cells. Overexpression of miR-325-3p dramatically inhibited cell proliferation and induced cell apoptosis. Conclusions: Our findings clearly demonstrated that introduction of miR-325-3p inhibited proliferation and induced apoptosis of Huh7-1.3 and HepG2.2.15 cells by directly decreasing AQP5 expression, and that silencing AQP5 expression was essential for the pro-apoptotic effect of miR-325-3p overexpression on Huh7-1.3 and HepG2.2.15 cells. It is beneficial to gain insight into the mechanism of HBV infection and pathophysiology of HBV-related HCC.


Assuntos
Apoptose , Aquaporina 5/genética , Carcinoma Hepatocelular/genética , Proliferação de Células , Neoplasias Hepáticas/genética , MicroRNAs/metabolismo , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/fisiopatologia , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Hepatite B/complicações , Humanos , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/fisiopatologia , MicroRNAs/fisiologia
4.
EBioMedicine ; 40: 198-209, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30738830

RESUMO

BACKGROUND: The resistance to EGF receptor (EGFR) tyrosine kinase inhibitors (TKI) is a major challenge in the treatment of non-small cell lung cancer (NSCLC). Understanding the molecular mechanisms behind resistance is therefore an important issue. Here we assessed the role of EGFR pathway substrate 8 (EPS8) and Forkhead box O 3a (FoxO3a) as potentially valuable targets in the resistance of NSCLC . METHODS: The expression levels of EPS8 and FoxO3a in patients with NSCLC (n = 75) were examined by immunohistochemistry staining, while in cells were detected by qPCR and western blot. The effects of EPS8 and FoxO3a on resistance, migration and invasion, cell cycle arrest were detected by MTT, transwell and flow cytometry, respectively. Chromatin immunoprecipitation and luciferase reporter assays were performed to determine the mechanisms of EPS8 expression and FoxO3a regulation. FINDINGS: We observed that the expression of EPS8 inversely correlated with FoxO3a in NSCLC cell lines and NSCLC patients. FoxO3a levels were significantly decreased in tumor tissues compared with para-carcinoma tissues, while EPS8 is opposite. Besides, they play reverse roles in the resistance to gefitinib, the migration and invasion abilities, the cell cycle arrest in vitro and the tumor growth in vivo. Mechanistically, FoxO3a inhibits EPS8 levels by directly binding its gene promoter and they form a negative loop in EGFR pathway. INTERPRETATION: Targeting FoxO3a and EPS8 in EGFR signaling pathway prevents the progression of NSCLC, which implied that the negative loop they formed could served as a therapeutic target for overcoming resistance in NSCLC. FUNDS: National Natural Science Foundation of China, Science and Technology Project of Henan, Outstanding Young Talent Research Fund of Zhengzhou University and the National Scholarship Fund.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Proteína Forkhead Box O3/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Apoptose/efeitos dos fármacos , Carcinoma Pulmonar de Células não Pequenas/patologia , Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/metabolismo , Feminino , Gefitinibe/farmacologia , Genes Reporter , Xenoenxertos , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/patologia , Camundongos , Modelos Biológicos , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos
5.
Hortic Res ; 5: 9, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29507733

RESUMO

Tomato is an important horticultural and economic crop cultivated worldwide. As Phytophthora infestans becomes a huge threat to tomato production, it is necessary to study the resistance mechanisms of tomato against P. infestans. Our previous research has found that miR482 might be involved in tomato-P. infestans interaction. In this study, miR482b precursor was cloned from Solanum pimpinellifolium "L3708" and miR482b was shown to decrease in abundance in tomato following P. infestans infection. Compared to wild-type tomato plants, tomato plants that overexpressed miR482b displayed more serious disease symptoms after P. infestans infection, with more necrotic cells, longer lesion diameters, and increased P. infestans abundance. Meanwhile, silencing of miR482b was performed by short tandem target mimic (STTM), resulting in enhancement of tomato resistance to P. infestans. Using miRNA and degradome data sets, NBS-LRR disease-resistance genes targeted by miR482b were validated. Negative correlation between the expression of miR482b and its target genes was found in all miR482b-overexpressing and -silencing tomato plants. Our results provide insight into tomato miR482b involved in the response to P. infestans infection, and demonstrate that miR482b-NBS-LRR is an important component in the network of tomato-P. infestans interaction.

6.
Plant Cell Physiol ; 59(4): 857-870, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29444327

RESUMO

Glycosylation mediated by UDP-dependent glycosyltransferase (UGT) is one of the most common reactions for the biosynthesis of small molecule glycosides. As glycosides have various biological roles, we characterized UGT genes from grapevine (Vitis vinifera). In silico analysis of VvUGT genes that were highly expressed in leaves identified UGT92G6 which showed sequence similarity to both monosaccharide and disaccharide glucoside-forming transferases. The recombinant UGT92G6 glucosylated phenolics, among them caffeic acid, carvacrol, eugenol and raspberry ketone, and also accepted geranyl glucoside and citronellyl glucoside. Thus, UGT92G6 formed mono- and diglucosides in vitro from distinct compounds. The enzyme specificity constant Vmax/Km ratios indicated that UGT92G6 exhibited the highest specificity towards caffeic acid, producing almost equal amounts of the 3- and 4-O-glucoside. Transient overexpression of UGT92G6 in Nicotiana benthamiana leaves confirmed the production of caffeoyl glucoside; however, the level of geranyl diglucoside was not elevated upon overexpression of UGT92G6, even after co-expression of genes encoding geraniol synthase and geraniol UGT to provide sufficient precursor. Comparative sequence and 3-D structure analysis identified a sequence motif characteristic for monoglucoside-forming UGTs in UGT92G6, suggesting an evolutionary link between mono- and disaccharide glycoside UGTs. Thus, UGT92G6 functions as a mono- and diglucosyltransferase in vitro, but acts as a caffeoyl glucoside UGT in N. benthamiana.


Assuntos
Dissacarídeos/metabolismo , Evolução Molecular , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Monossacarídeos/metabolismo , Vitis/enzimologia , Ácidos Cafeicos/farmacologia , Cimenos , Ensaios Enzimáticos , Glucosídeos/farmacologia , Cinética , Metaboloma , Modelos Moleculares , Monoterpenos/farmacologia , Fenóis/metabolismo , Filogenia , Extratos Vegetais/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Especificidade por Substrato , Terpenos/farmacologia
7.
Yi Chuan ; 36(1): 69-76, 2014 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-24846920

RESUMO

MicroRNAs (miRNAs) are a class of small endogenously RNA with an approximate length of 22nt which are known to be ubiquitous in eukaryotes. More importantly, miRNAs are key regulators of gene expression in eukaryotic cells through the degradation of target mRNA. The investigation on miRNAs in tomato that is an important model plant has made a great progress in recent years. Herein, by collecting the reported literature and miRBase, we found that 34 miRNAs in tomato are closely associated with pathogenicity. Subsequently, we predicted their target genes through bioinformatics approaches and built a disease-related regulatory network of miRNA and its target genes using Cytoscope program. This has led us to identify 13 miRNAs that are closely associated with pathogenicity in tomato from which we selected miR169, miR482, miR5300, miR6024, miR6026 and miR6027 for further analysis based on the association between miRNAs and the number of target genes. Lastly, we performed the analysis of target gene, promoter and real time quantitative PCR verification for these 6 miRNAs. Our study may pave the way for future in-depth analysis of biological action of miRNAs.


Assuntos
Biologia Computacional , Mineração de Dados , Lycopersicon esculentum/genética , MicroRNAs/genética , Doenças das Plantas/genética , Bases de Dados Genéticas , Redes Reguladoras de Genes , Genes de Plantas/genética , Predisposição Genética para Doença/genética , Regiões Promotoras Genéticas/genética
8.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 24(5): 571-3, 2007 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-17922430

RESUMO

OBJECTIVE: To explore the clinical cytogenetic features and prognosis of myeloid leukemia patients. METHODS: Bone marrow direct method and/or 24h culture without phytohaemagglutimin(PHA) were used to prepare the chromosomes and karyotype analysis was performed with R-banding and G-banding techniques. RESULTS: Among 420 patients with acute myeloid leukemia (AML), 223 cases were found to exhibit clonal chromosome abnormalities, accounted for 53.1%. t(8; 21), t(15; 17), inv(16)and del(11) were specifically associated with M2b, M3, M4Eo and M5 respectively. Out of 158 patients with chronic myeloid leukemia (CML), 96.8% (153/158) were found to exhibit clonal chromosome abnormalities. T(9;22) was specifically associated with CML and some cases of M0, M1 and M2. In these myeloid leukemia cases, there were 18 cases (AML 13 cases, CML 15 cases) without clonal chromosome abnormalities, accounted for 3.1% (18/578) and this phenomenon agreed with the diagnose of clinical signs, marrow morphology and immunology incompletely. CONCLUSION: Karyotype analysis was not only helpful to the diagnose and differential diagnose of myeloid leukemia, but also an important standard of the remission, relapse and therapeutic effect of myeloid leukemia. Chromosome analysis can be made exactly with the probe and FISH technique on the basic of chromosome karyotype analysis.


Assuntos
Leucemia Mieloide/diagnóstico , Leucemia Mieloide/genética , Leucemia Mieloide/patologia , Adolescente , Adulto , Idoso , Criança , Cromossomos Humanos/genética , Análise Citogenética , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Pessoa de Meia-Idade , Mutação , Prognóstico
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