Viral proteomics: The emerging cutting-edge of virus research

Zhou, ShengTao; Liu, Rui; Zhao, Xia; Huang, CanHua; Wei, YuQuan

Isobaric mass tags for relative and absolute quantitation (iTRAQ) allows simultaneous quantitation of protein extracts from host cells upon virus infection. Li et al. [19] utilized shotgun proteomics involving offline coupling of an LC system with MALDI-TOF/TOF MS/MS as a complementary approach to investigate the WSSV proteome. Forty-five viral proteins were identified, of which 13 were reported for the first time and seven were found to have acetylated N termini. RT-PCR confirmed the mRNA expression of 13 newly identified viral proteins. The iTRAQ technique was further used to differentiate the envelope proteins and nucleocapsid proteins of WSSV. Twenty-three envelope proteins and six nucleocapsid proteins were successfully identified based on iTRAQ ratios, demonstrating that iTRAQ is an effective approach for high throughput viral protein determination. iTRAQ labeling coupled with LC-MS/MS was also used to investigate the proteomes of a grouper embryonic cell line (GEC) infected with Singapore grouper iridovirus (SGIV) and uninfected GEC. Forty-nine viral proteins were recognized, among which 11 were reported for the first time. Furthermore, 743 host proteins were uncovered and categorized into 218 unique protein groups. Thus, iTRAQ analysis of SGIV infection in GEC provided a novel insight into viral and host gene products at the protein level [57] .