Nucleocytoplasmic transport of nucleocapsid proteins of enveloped RNA viruses

Abstract

Most viruses with non-segmented single stranded RNA genomes complete their life cycle in the cytoplasm of infected cells. However, despite undergoing replication in the cytoplasm, the structural proteins of some of these RNA viruses localize to the nucleus at specific times in the virus life cycle, primarily early in infection. Limited evidence suggests that this enhances successful viral replication by interfering with or inhibiting the host antiviral response. Nucleocapsid proteins of RNA viruses have a well-established, essential cytoplasmic role in virus replication and assembly. Intriguingly, nucleocapsid proteins of some RNA viruses also localize to the nucleus/nucleolus of infected cells. Their nuclear function is less well understood although significant advances have been made in recent years. This review will focus on the nucleocapsid protein of cytoplasmic enveloped RNA viruses, including their localization to the nucleus/nucleolus and function therein. A greater understanding of the nuclear localization of nucleocapsid proteins has the potential to enhance therapeutic strategies as it can be a target for the development of live-attenuated vaccines or antiviral drugs.

The FDA-approved drug ivermectin inhibits the replication of SARS-CoV-2 in vitro

“…The causative agent of the current COVID-19 pandemic, SARS-CoV-2, is a single stranded positive sense RNA virus that is closely related to severe acute respiratory syndrome coronavirus (SARS-CoV). Studies on SARS-CoV proteins have revealed a potential role for IMPα/β1 during infection in signal-dependent nucleocytoplasmic shutting of the SARS-CoV Nucleocapsid protein (Rowland et al, 2005;Timani et al, 2005;Wulan et al, 2015), that may impact host cell division (Hiscox et al, 2001;Wurm et al, 2001). In addition, the SARS-CoV accessory protein ORF6 has been shown to antagonize the antiviral activity of the STAT1 transcription factor by sequestering IMPα/β1 on the rough ER/Golgi membrane (Frieman et al, 2007).…”

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“…The NS1 protein of influenza virus prevents caspase-1 activation and the secretion of IL-1b and IL-18 via an unknown mechanism. The IL-1b and IL-18 pathways have been observed to be regulated by the vaccinia virus protein B15R and the molluscum contagiosum poxvirus proteins MC53L and MC54L, which can bind and inhibit IL-1b and IL-18, respectively [132,133]. Thus, the viral alkaline exonuclease of Epstein Barr virus (BGLF5) down-regulates molecules of the immune system such as TLR-2 and CD1 by degrading the mRNAs that encode them [134].…”

Firefly genomes illuminate parallel origins of bioluminescence in beetles

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