Virus Classification Based On Virus-Host Protein-protein Interaction Network

A Virus is a small infectious agent that can replicate only inside the living cells of other organisms.Most viruses are composed of a nucleic acid (DNA or RNA) and proteins, at the same time, are non-cell morphological parasitic life. The particles of viruses are small so that most of viruses are too small to be seen directly with a light microscope. The structure of viruses is generally simple, while the classification of different viruses is complicated. Currently, several systems, such as the ICTV system, the Baltimore classification, the LHT System, the Casjens and Kings Classification and so on, have been proposed to classify viruses and indicate the relationships between different viruses, each system has its limitations because of the complexity of virus origins and their rapid evolution rate.Many essential cellular processes such as cellular metabolism, transport and most regulatory mechanisms rely on physical interactions between proteins. Previous researches have informed us that a large amount of protein-protein interactions exist between virus proteins and different host proteins. Although some mechanisms and the effect of these protein-protein interactions between viruses and their host are still unknown, the accumulation of these protein-protein interactions offers us an alternative way to study the potential relations between different viruses. Thus the interaction network contains both virus proteins and host proteins are applied to evaluate the biological distances between different viruses. In this paper, 9683 protein-protein interactions concerning 114 viruses that host human, including HIV-1 viruses and HIV-2 viruses, are collected to measure the biological distances between different viruses.The functional similarities of human proteins that the proteins of certain viruses targeted are used to assess the potential relation between different viruses. The classification results demonstrated that our method can disclose the virus relationships, and is consistent with the taxonomic results from previous systems.It points to a new direction to where the functional relationships between viruses and hosts can be used to explore the virus relationship on a systematic level and be cherished as reference or complementary to the already existed systems.