| Summary: | 碩士 === 慈濟大學 === 醫學檢驗生物技術學系醫學生物技術碩士班 === 100 === Influenza A virus has been classified in the Orthomyxoviridae family. There are eight, single-stranded, negative-sensed RNA segments in the virions of influenza A viruses. Infection with influenza A virus will cause flu, respiratory illness and other severe diseases. Flu outbreaks could cause millions death. Three flu outbreaks occurred in the twentieth century, i.e. 1918 Spanish flu (H1N1), 1957 Asian flu (H2N2) and 1968 Hong Kong flu (H3N2).
Differential gene expression after influenza A virus infection in A549 cells was analyzed by microarray analysis in our previous study. Histone gene expression was found up-regulated in this assay. Up-regulation of histone expression after virus infection was also confirmed by real-time RT-PCR and Western blotting analysis. Furthermore, shRNA technology was used to knockdown histone genes in A549 cells, production of influenza A virus was inhibited significantly. Therefore, our results showed that histone expression did affect virus replication. However, which step of viral life cycle was affected by histones is unknown. To predict whether nucleosome which is composed of histones and viral nucleoprotein (NP) or matrix protein (M1) proteins interact with each other, software of bioinformatics was used. Both M1 and NP proteins could interact with nucleosome and histone octamer. To determine whether histones are associated with viral particles, the caesium chloride gradient centrifugation and sucrose gradient centrifugation to purify the intact viral particles and the glycerol gradient centrifugation to purify the ribonucleoproteins (RNPs) were conducted. Our results indicated that histones are associated with the viral particles and are in the same fraction with RNP.
The relationship between histone proteins and viral RNPs will be conducted further in the near future to clarify whether histone proteins and RNPs interacts directly.
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