DDX3 DEAD-Box RNA Helicase Is a Host Factor That Restricts Hepatitis B Virus Replication at the Transcriptional Level

Abstract

Upon entry into host cells, viruses encounter host factors that restrict viral infection. During evolution, viruses have acquired the ability to subvert cellular factors that adversely affect their replication. Such host factors include TRIM5α and APOBEC3G, which were discovered in retroviruses. The discovery of host restriction factors provided deeper insight into the innate immune response and viral pathogenesis, leading to better understanding of host-virus interactions. In contrast to the case with retroviruses, little is known about host factors that restrict hepatitis B virus (HBV), a virus distantly related to retroviruses. DDX3 DEAD box RNA helicase is best characterized as an RNA helicase involved in RNA metabolism, such as RNA processing and translation. Here, we show that DDX3 inhibits HBV infection at the level of viral transcription.