Influenza B virus (IBV) is one of the etiological agents that cause annual epidemics of seasonal influenza. According to the latest estimation, seasonal influenza claimed 300-600 thousand lives every year in the world, and IBV infection can account for over half of all the seasonal influenza cases.

Compared to influenza A virus (IAV), IBV causes more severe complications in children and old people, and the time from onset to death is shorter in fatal cases than IAV. Currently, much less basic research has been done on IBV than IAV, and little is known about many problems on IBV such as its interactions with hosts, its pathogenesis and the immune defense mechanisms of the host against it.

Prof. LIU Wenjun’s team at the Institute of Microbiology, Chinese Academy of Sciences (IMCAS) determined the transcriptome of human lung cell line A549 by high-thought sequencing and systematically analyzed the transcript response of this cell line to the infection of IBV.

Through GO annotation analysis, transcriptional factor target analysis, interferome analysis, KEGG enrichment analysis, it is discovered that type III interferons (IFN-λ1, λ2, λ3 and λ4) rather than type I IFNs (IFN-α/β) dominated-innate immune signaling cascades and extensive antiviral response are the remarkable characteristics in IBV-infected host cells. (On-line paper: https://www.tandfonline.com/doi/abs/10.1080/1040841X.2018.1446901?journalCode=imby20)

Bunyaviruses are a large group of segmented negative-strand RNA viruses, and they form one of the RNA virus groups that have the most number of members. Due to continuous discovery of new bunyaviruses, International Committee on Taxonomy of Viruses (ICTV) upgraded the previous family Bunyaviridae to the Bunyavirales, which contains nine families. Some bunyaviruses are arthropod-borne viruses which can cause lethal human diseases, such as Crimean-Congo hemorrhagic fever, Rift Valley fever, and the tick disease that outbreaks in recent years in China.

LIU’s group studied several aspects of the ribonucleoproteins (RNPs) of representative members in all the nine families of the Bunyavirales, including the atomic structures of RNP components, the patterns of their interactions, and their functional mechanisms in the life cycle of bunyaviruses. Based on these, a schematic model of the N and L proteins of bunyaviruses coordinating to fulfill the transcription of viral genome was proposed. (On-line paper: https://www.tandfonline.com/doi/abs/10.1080/1040841X.2018.1446901?journalCode=imby20）

The related results are published on-line with the famous international journals Protein & Cell and Critical Reviews in Microbiology on Jan. 13 and Mar. 6, respectively. Associated Professor LI Jing and Professor LIU Wenjun are the correspondence authors and Dr. SUN Yeping is the first author of these papers. These studies are supported by the projects including National Natural Science Foundation of China, the Key Research Program of Chinese Academy of Sciences and the National Key Research Program, etc.