The Host Protein Reticulon 3.1A Is Utilized by Flaviviruses to Facilitate Membrane Remodeling Turgut E. Aktepe, Susann Liebscher, Julia E. Prier, Cameron P. Simmons, and Jason M. Mackenzie Cell Reports. 2017 Nov 7;21(6):1639-1654. Speaker: Zi-Yi Lu (呂姿儀) Time: 15:10-16:00 Mar. 14, 2018 Commentator: Dr. Shang-Rung Wu (吳尚蓉老師) Place: Room 601 Abstract: Flaviviruses, which are enveloped and positive-sensed single stranded RNA viruses, contain many highly pathologic viruses, such as West Nile virus (WNV), Dengue virus (DENV), and Zika virus (ZIKV). Due to the limitation of their genome capacity, flaviviruses have been well known that they utility both viral and host factors to form intracellular membrane structures to enhance their replication [1, 2]. However, the exact mechanisms how these viral induced membrane structures form and what interactions between host and virus remain uncharacterized. The authors of this study identified a membrane-bound ER shaping protein, reticulon protein3.1A (RTN3.1A), as an important host factor during the replication cycles of the flaviviruses WNVKUN, DENV-2NGC, and ZIKVAFR. They found that RTN3.1A could recruit to and accumulate at the sites of viral replication complex structures. Once silencing of RTN3.1A, it would affect the capacity of flavivirus-induced membrane remolding. In addition, deficiency of RTN3.1A resulted in reducing viral RNA level, viral protein expression, and viral particle production. Furthermore, among these three flaviviruses, RTN3.1A co-localized and interacted only with WNVKUN-NS4A. The finding of this study have contributed to the understanding of host factors involving in viral membrane remodeling during flaviviruses infection. WNVKUN, DENV-2NGC, and ZIKVAFR all utilize the same host factor, RTN3.1A, but with subtle different manner to facilitate the biogenesis of viral induced membrane structures during their replication cycles. References: 1. Romero-Brey I, and Bartenschlager R. Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly. Viruses. 2016 Jun 7;8(6). 2. Westaway EG, Khromykh AA, and Mackenzie JM. Nascent flavivirus RNA colocalized in situ with double-stranded RNA in stable replication complexes. Virology. 1999 May 25;258(1):108-17.