RESUMEN

Endogenous ribonucleotides (RNs) and deoxyribonucleotides (dRNs) are important metabolites related to the pathogenesis of many diseases. In light of their physiological and pathological significances, a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). A one-step extraction of cells with 85% methanol followed by a simple derivatization reaction within 5 min at room temperature contributed to shortened analysis time. The derivatives of 22 nucleoside mono-, di- and triphosphates were retained on the typical C18 column and eluted by ammonium acetate and acetonitrile in 9 min. Under these optimal conditions, good linearity was achieved in the tested calibration ranges. The lower limit of quantitation (LLOQ) was determined to be 0.1-0.4 µM for the tested RNs and 0.001-0.1 µM for dRNs. In addition, the precision (CV) was <15% and the RSD of stability was lower than 10.4%. Furthermore, this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT 116 exposed to 10-hydroxycamptothecin. In conclusion, our method has proven to be simple, rapid, sensitive, and reliable. It may be used for specific expanded studies on intracellular pharmacology in vitro.

RESUMEN

BACKGROUND: Aberrant DNA repair pathways contribute to malignant transformation or disease progression and the acquisition of drug resistance in multiple myeloma (MM); therefore, these pathways could be therapeutically exploited. Ribonucleotide reductase (RNR) is the rate-limiting enzyme for the biosynthesis of deoxyribonucleotides (dNTPs), which are essential for DNA replication and DNA damage repair. In this study, we explored the efficacy of the novel RNR inhibitor, 4-hydroxysalicylanilide (HDS), in myeloma cells and xenograft model. In addition, we assessed the clinical activity and safety of HDS in patients with MM. METHODS: We applied bioinformatic, genetic, and pharmacological approaches to demonstrate that HDS was an RNR inhibitor that directly bound to RNR subunit M2 (RRM2). The activity of HDS alone or in synergy with standard treatments was evaluated in vitro and in vivo. We also initiated a phase I clinical trial of single-agent HDS in MM patients (ClinicalTrials.gov: NCT03670173) to assess safety and efficacy. RESULTS: HDS inhibited the activity of RNR by directly targeting RRM2. HDS decreased the RNR-mediated dNTP synthesis and concomitantly inhibited DNA damage repair, resulting in the accumulation of endogenous unrepaired DNA double-strand breaks (DSBs), thus inhibiting MM cell proliferation and inducing apoptosis. Moreover, HDS overcame the protective effects of IL-6, IGF-1 and bone marrow stromal cells (BMSCs) on MM cells. HDS prolonged survival in a MM xenograft model and induced synergistic anti-myeloma activity in combination with melphalan and bortezomib. HDS also showed a favorable safety profile and demonstrated clinical activity against MM. CONCLUSIONS: Our study provides a rationale for the clinical evaluation of HDS as an anti-myeloma agent, either alone or in combination with standard treatments for MM. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03670173, Registered 12 September 2018.

Asunto(s)

Mieloma Múltiple , Ribonucleótido Reductasas , Roturas del ADN de Doble Cadena , Daño del ADN , Reparación del ADN , Replicación del ADN , Humanos , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/genética , Ribonucleótido Reductasas/genética , Ribonucleótido Reductasas/metabolismo

RESUMEN

Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltri-fluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85％methanol followed by a simple derivatization reaction within 5 min at room temper-ature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical Cig column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4 μM for the tested RNs and 0.001-0.1 μM for dRNs.In addition,the precision(CV)was＜15％and the RSD of stability was lower than 10.4％.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.

RESUMEN

Eukaryotic ribonucleotide reductases are iron-dependent enzymes that catalyze the rate-limiting step in the de novo synthesis of deoxyribonucleotides. Multiple mechanisms regulate the activity of ribonucleotide reductases in response to genotoxic stresses and iron deficiency. Upon iron starvation, the Saccharomyces cerevisiae Aft1 transcription factor specifically binds to iron-responsive cis elements within the promoter of a group of genes, known as the iron regulon, activating their transcription. Members of the iron regulon participate in iron acquisition, mobilization and recycling, and trigger a genome-wide metabolic remodeling of iron-dependent pathways. Here, we describe a mechanism that optimizes the activity of yeast ribonucleotide reductase when iron is scarce. We demonstrate that Aft1 and the DNA-binding protein Ixr1 enhance the expression of the gene encoding for its catalytic subunit, RNR1, in response to iron limitation, leading to an increase in both mRNA and protein levels. By mutagenesis of the Aft1-binding sites within RNR1 promoter, we conclude that RNR1 activation by iron depletion is important for Rnr1 protein and deoxyribonucleotide synthesis. Remarkably, Aft1 also activates the expression of IXR1 upon iron scarcity through an iron-responsive element located within its promoter. These results provide a novel mechanism for the direct activation of ribonucleotide reductase function by the iron-regulated Aft1 transcription factor.

Asunto(s)

Deficiencias de Hierro , Ribonucleótido Reductasas/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Factores de Transcripción/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Regulación Fúngica de la Expresión Génica , Proteínas del Grupo de Alta Movilidad/genética , Proteínas del Grupo de Alta Movilidad/metabolismo , Hierro/metabolismo , Unión Proteica , Elementos de Respuesta , Ribonucleótido Reductasas/metabolismo , Saccharomyces cerevisiae , Factores de Transcripción/genética , Activación Transcripcional

RESUMEN

In an effort to understand the molecular events contributing to the cytotoxicity activity of resveratrol (RSV), we investigated its effects on human lung adenocarcinoma epithelial cell line A549 at different concentrations. Cellular nucleoside metabolic profiling was determined by an established liquid chromatography-mass spectrometry method in A549 cells. RSV resulted in significant decreases and imbalances of deoxyribonucleoside triphosphates (dNTPs) pools suppressing subsequent DNA synthesis. Meanwhile, RSV at high concentration caused significant cell cycle arrest at S phase, in which cells required the highest dNTPs supply than other phases for DNA replication. The inhibition of DNA synthesis thus blocked subsequent progression through S phase in A549 cells, which may partly contribute to the cytotoxicity effect of RSV. However, hydroxyurea (HU), an inhibitor of RNR activity, caused similar dNTPs perturbation but no S phase arrest, finally no cytotoxicity effect. Therefore, we believed that the dual effect of high concentration RSV, including S phase arrest and DNA synthesis inhibition, was required for its cytotoxicity effect on A549 cells. In summary, our results provided important clues to the molecular basis for the anticancer effect of RSV on epithelial cells.

Asunto(s)

Adenocarcinoma del Pulmón/patología , Ciclo Celular/efectos de los fármacos , Desoxirribonucleótidos/metabolismo , Células Epiteliales/efectos de los fármacos , Neoplasias Pulmonares/patología , Resveratrol/farmacología , Células A549 , Adenocarcinoma del Pulmón/metabolismo , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Hidroxiurea/farmacología , Neoplasias Pulmonares/metabolismo , Puntos de Control de la Fase S del Ciclo Celular/efectos de los fármacos

RESUMEN

In an effort to understand the molecular events contributing to the cytotoxicity activity of resveratrol (RSV), we investigated its effects on human lung adenocarcinoma epithelial cell line A549 at different concentrations. Cellular nucleoside metabolic profiling was determined by an established liquid chromatography-mass spectrometry method in A549 cells. RSV resulted in significant decreases and imbalances of deoxyribonucleoside triphosphates (dNTPs) pools suppressing subsequent DNA synthesis. Meanwhile, RSV at high concentration caused significant cell cycle arrest at S phase, in which cells required the highest dNTPs supply than other phases for DNA replication. The inhibition of DNA synthesis thus blocked subsequent progression through S phase in A549 cells, which may partly contribute to the cytotoxicity effect of RSV. However, hydroxyurea (HU), an inhibitor of RNR activity, caused similar dNTPs perturbation but no S phase arrest, finally no cytotoxicity effect. Therefore, we believed that the dual effect of high concentration RSV, including S phase arrest and DNA synthesis inhibition, was required for its cytotoxicity effect on A549 cells. In summary, our results provided important clues to the molecular basis for the anticancer effect of RSV on epithelial cells.

RESUMEN

The purpose of this study was to investigate the inhibitory effect of ZH-1 ((6S,9aS,6aR,9bR)-6-(phenylcarbonyl)-6,6a,9a,9b-tetrahydro-8H-azolidino[3,4-a]b enzo [e]indolizine-7,9-dione) and its potential interaction with gemcitabine in A549 cells. MTT assay showed that the combined use of gemcitabine and ZH-1 presented a significant inhibition effect on A549 cell growth with the cell viability from 82.3 ±â€¯5.6% to 51.0 ±â€¯6.6%. The CI value was 0.60 suggesting a synergistic effect between these two drugs. HPLC-MS/MS data indicated that combined treatment with gemcitabine and ZH-1 induced a significant decrease in deoxyadenosine triphosphate, deoxycytidine triphosphate, deoxyguanosine triphosphate and deoxythymidine triphosphate levels compared with use of gemcitabine alone. Five RNs as well as seven dRNs were considered to be significantly contributive to the discrimination of samples. Furthermore, western blot analysis revealed that the combination treatment caused A549 cell apoptosis via the intrinsic pathway by up-regulating Bax/Bcl-2 ratio, activating caspase-9, caspase-3 and poly-ADP-ribose polymerase, and promoting caspase-7, caspase-9 and poly-ADP-ribose polymerase cleavage. Collectively, the combined treatment with gemcitabine and ZH-1 exerted a strong synergistic action on anticancer activity through growth inhibition, perturbations in ribonucleotides and deoxyribonucleotides and the activation of intrinsic apoptotic signaling pathway.

Asunto(s)

Antimetabolitos Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Desoxicitidina/análogos & derivados , Desoxirribonucleótidos/síntesis química , Células A549 , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Desoxicitidina/farmacología , Humanos , Gemcitabina

RESUMEN

A tightly controlled cellular deoxyribonucleotide (deoxynucleoside triphosphate [dNTP]) pool is critical for maintenance of genome integrity. One mode of dNTP pool regulation is through subcellular localization of ribonucleotide reductase (RNR), the enzyme that catalyzes the rate-limiting step of dNTP biosynthesis. In Saccharomyces cerevisiae, the RNR small subunit, Rnr2-Rnr4, is localized to the nucleus, whereas the large subunit, Rnr1, is cytoplasmic. As cells enter S phase or encounter DNA damage, Rnr2-Rnr4 relocalizes to the cytoplasm to form an active holoenzyme complex with Rnr1. Although the DNA damage-induced relocalization requires the checkpoint kinases Mec1-Rad53-Dun1, the S-phase-specific redistribution does not. Here, we report that the S-phase cyclin-cyclin-dependent kinase (CDK) complex Clb6-Cdc28 controls Rnr2-Rnr4 relocalization in S phase. Rnr2 contains a consensus CDK site and exhibits Clb6-dependent phosphorylation in S phase. Deletion of CLB6 or removal of the CDK site results in an increased association of Rnr2 with its nuclear anchor Wtm1, nuclear retention of Rnr2-Rnr4, and an enhanced sensitivity to the RNR inhibitor hydroxyurea. Thus, we propose that Rnr2-Rnr4 redistribution in S phase is triggered by Clb6-Cdc28-mediated phosphorylation of Rnr2, which disrupts the Rnr2-Wtm1 interaction and promotes the release of Rnr2-Rnr4 from the nucleus.

Asunto(s)

Proteína Quinasa CDC28 de Saccharomyces cerevisiae/metabolismo , Ciclina B/metabolismo , Ribonucleósido Difosfato Reductasa/metabolismo , Ribonucleótido Reductasas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/citología , Proteína Quinasa CDC28 de Saccharomyces cerevisiae/análisis , Ciclina B/análisis , Fosforilación , Transporte de Proteínas , Ribonucleósido Difosfato Reductasa/análisis , Ribonucleótido Reductasas/análisis , Fase S , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/análisis

RESUMEN

The absolute and relative pool sizes of deoxyribonucleotides (dRNs) are essential in DNA replication fidelity, DNA damage and repair. We found in this study that although DNA damage induced by methyl methanesulfonate (MMS) seemed similar in cancer (HepG2) and normal (LO2) cells, more extensive alterations in ribonucleotides (RNs) and dRNs pools occurred in HepG2 cells indicating that HepG2 cells were more vigilant to DNA damage. After 10 h repair, RNs pools were still severely perturbed in LO2 cells. Compared to LO2 cells, deoxyribonucleotide triphosphates (dNTPs) pools in HepG2 cells elevated by more folds which could facilitate more efficient DNA repair and improve survival probability following DNA damage, although this should definitely lead to higher mutation rates. DNA repair was more efficient in HepG2 cells at S phase and it partly came to an end while DNA repair was still uncompleted in LO2 cells outside S phase. In conclusion, our results demonstrated that HepG2 and LO2 cells presented many differences in nucleotide metabolism, cell cycle checkpoints and DNA repair pathways in response to DNA damage, which could be potential targets for cancer treatment.

RESUMEN

Balanced deoxyribonucleotides pools are essential for cell survival and genome stability. Ribonucleotide reductase is the rate-limiting enzyme for the production of deoxyribonucleotides. We report here that p53 suppresses ribonucleotide reductase subunit 1 (RRM1) and 2 (RRM2) via inhibiting mammalian target of rapamycin complex 1 (mTORC1). In vitro, cancer cell lines and mouse embryonic fibroblast cells were treated with different concentrations of pharmacological inhibitors for different times. In vivo, rhabdomyosarcoma Rh30 cell tumor-bearing mice were treated with rapamycin or AZD8055. Protein levels and phosphorylation status were assessed by immunoblotting and mRNA levels were determined by real time RT-PCR. Pharmacological inhibition of mTORC1 with rapamycin, mTOR kinase with AZD8055 or protein kinase B with MK2206 resulted in decrease of RRM1 and RRM2 in Rh30 cells both in vitro and in mouse tumor xenografts. Moreover, eukaryotic translational initiation factor 4E-binding proteins 1 and 2 double knockout mouse embryonic fibroblast cells demonstrated an elevation of RRM1 and RRM2. Furthermore, down-regulation of mTOR-protein kinase B signaling or cyclin dependent kinase 4 led to decrease of RRM1 and RRM2 mRNAs. In addition, TP53 mutant cancer cells had elevation of RRM1 and RRM2, which was reduced by rapamycin. Importantly, human double minute 2 inhibitor nutlin-3 decreased RRM1 and RRM2 in TP53 wild type rhabdomyosarcoma Rh18 but not in TP53 mutated Rh30 cells. Our data demonstrated that mTOR enhances the cap-dependent protein translation and gene transcription of RRM1 and RRM2. Our findings might provide an additional mechanism by which p53 maintains genome stability.

Asunto(s)

Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Neoplasias/metabolismo , Ribonucleósido Difosfato Reductasa/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Células A549 , Animales , Línea Celular Tumoral , Células Cultivadas , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Compuestos Heterocíclicos con 3 Anillos/farmacología , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina/antagonistas & inhibidores , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Ratones Noqueados , Ratones SCID , Morfolinas/farmacología , Mutación , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Interferencia de ARN , Ribonucleósido Difosfato Reductasa/genética , Sirolimus/farmacología , Proteína p53 Supresora de Tumor/genética , Proteínas Supresoras de Tumor/genética , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

The aim of this study was to investigate the antitumor activities of Phyllanthus amarus (PHA) and its potential of herb-drug interactions with 5-Fluorouracil (5-FU). Cell viability, ribonucleotides (RNs) and deoxyribonucleotides (dRNs) levels, cell cycle distribution, and expression of thymidylate synthase (TS) and ribonucleotide reductase (RR) proteins were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) method, flow cytometry and Western blot analysis, respectively. Our standardized PHA extract showed toxicity to HepG2 cells at high concentrations after 72 h exposure and induced G2/M cell cycle arrest. Combined use of 5-FU with PHA resulted in significant decreases in ATP, CTP, GTP, UTP and dTTP levels, while AMP, CMP, GMP and dUMP levels increased significantly compared with use of 5-FU alone. Further, PHA could increase the role of cell cycle arrest at S phase induced by 5-FU. Although PHA alone had no direct impact on TS and RR, PHA could change the levels of RNs and dRNs when combined with 5-FU. This may be due to cell cycle arrest or regulation of key enzyme steps in intracellular RNs and dRNs metabolism.

RESUMEN

The mevalonate pathway is tightly linked to cell division. Mevalonate derived non-sterol isoprenoids and cholesterol are essential for cell cycle progression and mitosis completion respectively. In the present work, we studied the effects of fluoromevalonate, a competitive inhibitor of mevalonate diphosphate decarboxylase, on cell proliferation and cell cycle progression in both HL-60 and MOLT-4 cells. This enzyme catalyzes the synthesis of isopentenyl diphosphate, the first isoprenoid in the cholesterol biosynthesis pathway, consuming ATP at the same time. Inhibition of mevalonate diphosphate decarboxylase was followed by a rapid accumulation of mevalonate diphosphate and the reduction of ATP concentrations, while the cell content of cholesterol was barely affected. Strikingly, mevalonate diphosphate decarboxylase inhibition also resulted in the depletion of dNTP pools, which has never been reported before. These effects were accompanied by inhibition of cell proliferation and cell cycle arrest at S phase, together with the appearance of γ-H2AX foci and Chk1 activation. Inhibition of Chk1 in cells treated with fluoromevalonate resulted in premature entry into mitosis and massive cell death, indicating that the inhibition of mevalonate diphosphate decarboxylase triggered a DNA damage response. Notably, the supply of exogenously deoxyribonucleosides abolished γ-H2AX formation and prevented the effects of mevalonate diphosphate decarboxylase inhibition on DNA replication and cell growth. The results indicate that dNTP pool depletion caused by mevalonate diphosphate decarboxylase inhibition hampered DNA replication with subsequent DNA damage, which may have important consequences for replication stress and genomic instability.

Asunto(s)

Carboxiliasas/metabolismo , Desoxirribonucleósidos/metabolismo , Linfocitos/efectos de los fármacos , Ácido Mevalónico/farmacología , Adenosina Trifosfato/metabolismo , Carboxiliasas/antagonistas & inhibidores , Carboxiliasas/genética , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Daño del ADN , Replicación del ADN/efectos de los fármacos , Desoxirribonucleósidos/farmacología , Regulación de la Expresión Génica , Células HL-60 , Halogenación , Hemiterpenos/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Linfocitos/citología , Linfocitos/metabolismo , Ácido Mevalónico/análogos & derivados , Ácido Mevalónico/metabolismo , Compuestos Organofosforados/metabolismo , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal

RESUMEN

Objective To evaluate thetherapeutic effect of sodium deoxyribonucleotide injection at Zusanli point for chemotherapy-induced leukopenia in patients with lung cancer.MethodsA total of 116 chemotherapy-induced leukopenia patients with lung cancer were randomly divided into a therapy group and a control group, 60 in the treatment group and 56 in the control group. The patients in the treatment group were treated with sodium deoxyribonucleotide injection atZusnlipoint, and those in the control group were treated with vein injection of sodium deoxyribonucleotide.Results The total effective rate in the treatment group was significant higher than that in the control group (91.7%vs.76.8%;χ2=4.890,P=0.032). The effective rates on days 3,5,7 and 10 in the treatment group were also significant higher than those in the control group (on day 3: 51.7%vs. 32.1%,χ2=4.530,P=0.036; on day 5: 76.7%vs. 53.6%,χ2=6.840,P=0.018; on day 7: 85.0%vs. 67.9%,χ2=4.770,P=0.026; on day 10: 78.3%vs. 53.6%,χ2=7.960,P=0.011).Conclusion Sodium deoxyribonucleotide injection atZusanlipoint has definite efficacy for chemotherapy-induced leukopenia in patients with lung cancer.

RESUMEN

The ribonucleotide reductase (RNR) enzyme is a heteromer of RRM1 and RRM2 subunits. The active enzyme catalyzes de novo reduction of ribonucleotides to generate deoxyribonucleotides (dNTPs), which are required for DNA replication and DNA repair processes. Complexity in the generation of physiologically relevant, active RRM1/RRM2 heterodimers was perceived as limiting to the identification of selective RRM1 inhibitors by high-throughput screening of compound libraries and led us to seek alternative methods to identify lead series. In short, we found that gemcitabine, as its diphosphate metabolite, represents one of the few described active site inhibitors of RRM1. We herein describe the identification of novel 5'-amino gemcitabine analogs as potent RRM1 inhibitors through in-cell phenotypic screening.

Asunto(s)

Desoxicitidina/análogos & derivados , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Línea Celular Tumoral , Desoxicitidina/química , Desoxicitidina/farmacología , Relación Dosis-Respuesta a Droga , Ensayos Analíticos de Alto Rendimiento , Humanos , Espectroscopía de Resonancia Magnética , Estructura Molecular , Ribonucleósido Difosfato Reductasa , Relación Estructura-Actividad , Gemcitabina

RESUMEN

We studied the sub-population level evolution of a duck influenza A virus isolate during passage in swine tracheal cells. The complete genomes of the A/mallard/Netherlands/10-Nmkt/1999 strain and its swine cell-passaged descendent were analysed by 454 pyrosequencing with coverage depth ranging from several hundred to several thousand reads at any point. This allowed characterization of defined minority sub-populations of gene segments 2, 3, 4, 5, 7, and 8 present in the original isolate. These minority sub-populations ranged between 9.5% (for segment 2) and 46% (for segment 4) of their respective gene segments in the parental stock. They were likely contributed by one or more viruses circulating within the same area, at the same period and in the same or a sympatric host species. The minority sub-populations of segments 3, 4, and 5 became extinct upon viral passage in swine cells, whereas the minority sub-populations of segments 2, 7 and 8 completely replaced their majority counterparts. The swine cell-passaged virus was therefore a three-segment reassortant and also harboured point mutations in segments 3 and 4. The passaged virus was more homogenous than the parental stock, with only 17 minority single nucleotide polymorphisms present above 5% frequency across the whole genome. Though limited here to one sample, this deep sequencing approach highlights the evolutionary versatility of influenza viruses whereby they exploit their genetic diversity, predilection for mixed infection and reassortment to adapt to a new host environmental niche.

Asunto(s)

Evolución Molecular , Virus de la Influenza A/genética , Gripe Aviar/virología , Análisis de Secuencia de ADN/métodos , Animales , Animales Salvajes , Línea Celular , Coinfección/virología , Patos , Secuenciación de Nucleótidos de Alto Rendimiento , Virus de la Influenza A/clasificación , Polimorfismo de Nucleótido Simple , ARN Viral/análisis , ARN Viral/química , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Porcinos

RESUMEN

AIM:To analyse sequences of p62 dok amino acid and cDNA and to investigate p62 dok tyrosine phosphorylation and its relation with p21 ras GAP. METHODS:The purified p62 dok was extracted from CHO/IR cells. The peptide sequence of p62 dok was carried out on a high performance analyzer. PCR was performed with the primers designed from the sequence of p62 dok amino acid. Western blot and immunoprecipitation were used to identify tyrosine phosphorylation of p62 dok and the binding of p62 dok with p21 ras GAP. RESULTS:The p62 dok cDNA is a 1863 bp sequence and code 481 amino acid with 15 tyrosine residues and a putative pleckstrin homology domain. The p62 dok protein is rich in PxxP motif. The tyrosine-phosphorylated p62 dok can bind p21 ras GAP. CONCLUSION:Perhaps p62 dok is a new signaling molecule and play an important role in insulin signaling networks through RAS/MAPK pathway.