Transcription factor p53 inhibits dengue virus infection through typeⅠinterferon signaling pathway / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the role of a transcription factor p 53 in dengue virus infec-tion.Methods A plasmid expressing siRNA specific for p 53 gene was constructed and then used to prepare HepG2 cell line with a suppressed expression of p 53 protein.The expression of p53 protein was detected by Western blot assay .A wild type control group and a siRNA group were set up by infecting wildtype HepG 2 cells and p53 low expressing HepG2 cells with type 2 dengue viruses,respectively.The virus titers in two dif-ferent cells were determined by plaque forming assay using Vero cells .Indirect immunofluorescence assay was performed to detect virus multiplication .The apoptosis of virus infected cells were analyzed by flow cytome-try.ELISA was performed to analyze the levels of IFN-βsecreted by infected cells from two groups .Results Compared with wildtype control group ,the cells in siRNA group showed a suppressed expression of p 53 pro-tein,suggesting that the HepG2 cell line with low p53 protein expression was successfully established .The vi-rus titer in supernatants of the cells from siRNA group was about 100-fold higher than that of wildtype control group at 24 hours after viral infection .Fluorescence activated cell sorting analysis showed that the numbers of green fluorescence labeled cells were remarkably increased in siRNA group .We speculated that p53 protein might play a role in the inhibition of dengue virus infection as indicated by the observed results .The numbers of apoptotic cells showed no significant difference between two groups .However,the level of IFN-βsecreted by wildtype HepG2 cells was six times higher than that of the cells in siRNA group .Conclusion p53 pro-tein might inhibit dengue virus infection through the activation of type Ⅰ interferon signaling pathway rather than enhance cell apoptosis .