Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located...Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production.展开更多
A two-period duopoly model is developed to examine the competitive effects of targeted advertising with customer recognition （TACR）. In the model, two competing firms sell goods to end consumers in the first period,...A two-period duopoly model is developed to examine the competitive effects of targeted advertising with customer recognition （TACR）. In the model, two competing firms sell goods to end consumers in the first period, during which customer recognition is obtained. In the second period, advertising can be targeted toward different consumer types. Advertising is assumed to be persuasive in the way that consumer valuation is increased. Equilibrium decisions and profits in each period are derived, showing that the firm who loses the current competition will win in the future. As a result, forward-looking firms price less aggressively so that their long-term profits can be enhanced with the help of TACR. Particularly, TACR improves profits through three important effects： valuation increasing, customer poaching, and anti-competition. Finally, this paper investigates the welfare issues, showing that firms enhance profits at the expense of consumer surplus. It is, therefore, suggested that public sectors take a step to protect consumers with the rapid development of targeting technology.展开更多
文摘Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production.
基金The National Natural Science Foundation of China(No.71071033)the Research and Innovation Project for College Graduates of Jiangsu Province(No.CXZZ-0186)
文摘A two-period duopoly model is developed to examine the competitive effects of targeted advertising with customer recognition （TACR）. In the model, two competing firms sell goods to end consumers in the first period, during which customer recognition is obtained. In the second period, advertising can be targeted toward different consumer types. Advertising is assumed to be persuasive in the way that consumer valuation is increased. Equilibrium decisions and profits in each period are derived, showing that the firm who loses the current competition will win in the future. As a result, forward-looking firms price less aggressively so that their long-term profits can be enhanced with the help of TACR. Particularly, TACR improves profits through three important effects： valuation increasing, customer poaching, and anti-competition. Finally, this paper investigates the welfare issues, showing that firms enhance profits at the expense of consumer surplus. It is, therefore, suggested that public sectors take a step to protect consumers with the rapid development of targeting technology.
