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Ras-GTPase-activating protein (SH3 domain)-binding protein (G3BP) is an RNA binding protein. G3BP is a key component of stress granules (SGs) and can interact with many host proteins to regulate the expression of SGs. As an antiviral factor, G3BP can interact with viral proteins to regulate the assembly of SGs and thus exert antiviral effects. However, many viruses can also use G3BP as a proximal factor and recruit translation initiation factors to promote viral proliferation. G3BP regulates mRNA translation and attenuation to regulate gene expression; therefore, it is closely related to diseases, such as cancer, embryonic death, arteriosclerosis, and neurodevelopmental disorders. This review discusses the important discoveries and developments related G3BP in the biological field over the past 20 years, which includes the formation of SGs, interaction with viruses, stability of RNA, and disease progression.

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ADN Helicasas/química , ADN Helicasas/metabolismo , Proteínas de Unión a Poli-ADP-Ribosa/química , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , ARN Helicasas/química , ARN Helicasas/metabolismo , Proteínas con Motivos de Reconocimiento de ARN/química , Proteínas con Motivos de Reconocimiento de ARN/metabolismo , Animales , Gránulos Citoplasmáticos/metabolismo , ADN Helicasas/genética , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno , Humanos , Proteínas de Unión a Poli-ADP-Ribosa/genética , Unión Proteica , Dominios Proteicos , Dominios y Motivos de Interacción de Proteínas , ARN Helicasas/genética , Proteínas con Motivos de Reconocimiento de ARN/genética , Virus ARN/fisiología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Investigación , Estrés Fisiológico , Relación Estructura-Actividad , Replicación Viral

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INTRODUCTION: Porcine epidemic diarrhoea virus (PEDV) infection causes watery diarrhoea, vomiting, anorexia, and weight loss, especially among neonatal piglets, inflicting on them morbidity and mortality potentially reaching 90%-100%. Despite it being known that certain mammalian cell phases are arrested by PEDV, the mechanisms have not been elucidated, and PEDV pathogenesis is poorly understood. This study determined the effect of an epidemic PEDV strain on cell cycle progression. MATERIAL AND METHODS: We observed the effect of the PEDV SHpd/2012 strain on an infected Vero cell cycle through flow cytometry and Western blot, investigating the interrelationships of cell-cycle arrest, the DNA damage-signalling pathway caused by PEDV and the phosphorylation levels of the key molecules Chk.2 and H2A.X involved upstream and downstream in this pathway. RESULTS: PEDV induced Vero cell-cycle arrest at the G1/G0 phase. The phosphorylation levels of Chk.2 and H2A.X increased with the prolongation of PEDV infection, and no significant cell-cycle arrest was observed after treatment with ATM or Chk.2 inhibitors. The proliferation of PEDV was also inhibited by treatment with ATM or Chk.2 inhibitors. CONCLUSION: PEDV-induced cell-cycle arrest is associated with activation of DNA damage-signalling pathways. Our findings elucidate the molecular basis of PEDV replication and provide evidence to support further evaluation of PEDV pathogenesis.

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Objective To establish an enterovirus 71(EV71) infection model of tree shrew primary renal cells.Methods Tree shrew primary renal cells were obtained by trypsin digestion.After subculture and purification,EV71 virus was used to infect these primary cells.The culture supernatant of these EV71-infected cells was collected for virus titer detection at 1,2,4,6 and 8 days post-infection.The cells were collected for detection of EV71 VP1 protein by Western blot assay.Furthermore,the expression and location of VP1 protein in the infected cells were detected by indirect immunofluorescence assay.Vero cells were taken as positive control to evaluate the infectivity of EV71 virus to tree shrew primary renal cells.Results Morphologically,the cultured cells were proved to be majorly consisted of the primary renal cells after subculture and purification.The obtained primary cells were infected by EV71 virus.The virus titer was up to 1.3×106 TCID 50/mL during 48-96 h post-infection,proving that EV71 virus infected and proliferated in the tree shrew primary renal cells.Western blot showed that the viral VP1 protein was detected from infected primary cells at 2 to 8 d post infection.VP1 protein was also observed in the cytoplasm at 2 to 6 d post infection by indirect immunofluorescence.Compared with Vero cells,the infectivity of EV71 virus to tree shrew primary renal cells and its proliferation were confirmed.Conclusions Based on the successful establishment of cell culture of tree shrew primary renal cells,the infectivity to the obtained cells and proliferation of EV71 virus in the cells are confirmed.The model of EV71 virus-infected tree shrew primary renal cells is initially established.

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Objective To explore the proliferation characteristics of primary small intestinal epithelial cells of tree shrews and the characteristics of human rotavirus(RV) G1P[8] infection to these cells,and establish a model of tree shrew primary small intestinal epithelial cells infected with human rotavirus G1P[8].Methods The primary small intestinal epithelial cells were obtained by collagenase Ⅺ and dispase I digestion from tree shrew.After purification and identification,the obtained primary small intestinal epithelial cells were infected with RV.Then,culture supernatants of infected cells were collected every 12 hours after infection.Viral titer and viral load were subsequently determined.Western blot and indirect immunofluorescence observation were used to detect the expression of RV protein VP6 in the primary cells.The infectivity of RV to the tree shrew primary cells was finally evaluated.Results After purification and identification of primary epithelial cells from the tree shrew,high purity above 90% primary tree shrew small intestinal epithelial cells was obtained.These primary small intestinal epithelial cells could be infected with RV virus by comparing the virus infectivity to primary renal cells,HCT116 cells and MA104 cells.The virus titer reached to 2.0×105TCID 50/mL at 72 h after infection.Using Western blot and indirect immunofluorescence observation,the specific viral protein of VP6 was determined to be expressed in the tree shrew primary small intestinal epithelial cells,and were located in the cytoplasm from days 1 to 5.Conclusions The separation,purification and cultivation methods of tree shrew primary small intestinal epithelial cells are successful,and the tree shrew model of RV-infected the tree shrew primary small intestinal epithelial cells is successfully established.

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Hemocytes are the major immune cells of crustaceans which are believed to be essential for the pathogenesis of white spot syndrome virus (WSSV) infection. Crayfish hemocytes and hematopoietic tissue (HPT) cells have been found to be susceptible to WSSV infection, but the procedure of WSSV infection to both cell types has not yet been carefully investigated. In this study, we analyzed the infection and proliferation of WSSV in crayfish hemocytes as well as HPT cells in detail through transmission electronic microscopy (TEM). The results showed that WSSV could enter both hemocytes and HPT cells through endocytosis, but the production of progeny virus was only achieved in HPT cells. Further investigation demonstrated that although WSSV could transcribe its genes in both cell types, viral genome replication and structural protein expression were unsuccessful in hemocytes, which may be responsible for the failure of progeny production. Therefore, we propose that both hemocytes and HPT cells are susceptible to WSSV infection but only HPT cells are permissive to WSSV replication. These findings will extend our knowledge of the interaction between WSSV and the host immune system.

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Astacoidea/genética , Astacoidea/virología , Virus del Síndrome de la Mancha Blanca 1/fisiología , Animales , Células Cultivadas , Expresión Génica , Genoma , Células Madre Hematopoyéticas/virología , Hemocitos/virología , Replicación Viral

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AIM: The aim of this study was to determine the concentration of salivary B2M as a marker of viral proliferation in HBS Ag(+), HBV DNA PCR(+) and Hbs Ag(+) and HBV DNA PCR(-) subjects. BACKGROUND: Beta-2 microglobulin (B2M) is responsible for transmission of viral antigens such as Hepatitis B (HBV) on the surface of liver cells as part of an HLA complex. PATIENTS AND METHODS: In this case control study, 25 PCR(+) and 2 PCR(-) patients were included. 5 mL of the saliva sample was obtained from all patients and salivary B2M level was measured using nephelometer. The data was evaluated by the descriptive, chi square and t tests. RESULTS: 72% of the PCR(+) patients received medications and in contrast, 85.7% of the patients with PCR(-) did not take any medication (P < 0.001). The average salivary concentration ofBeta-2 microglobulin in the PCR(+) group (5.28 ± 5.45 mg/deciliter) was more than PCR(-) group (1.51±0.77) and this difference was statistically significant (P = 0.003). CONCLUSION: The salivary B2Mlevel can be used as a marker of viral proliferation in patients with hepatitis B.