In recent years, ultrastructural studies of viral surface spikes from three different genera within the Bunyaviridae family have revealed a remarkable diversity in their spike organization. Despite this structural heterogeneity, in every case the spikes seem to be composed of heterodimers formed by Gn and Gc envelope glycoproteins. In this review, current knowledge of the Gn and Gc structures and their functions in virus cell entry and exit is summarized. During virus cell entry, the role of Gn and Gc in receptor binding has not yet been determined. Nevertheless, biochemical studies suggest that the subsequent virus-membrane fusion activity is accomplished by Gc. Further, a class II fusion protein conformation has been predicted for Gc of hantaviruses, and novel crystallographic data confirmed such a fold for the Rift Valley fever virus (RVFV) Gc protein. During virus cell exit, the assembly of different viral components seems to be established by interaction of Gn and Gc cytoplasmic tails (CT) with internal viral ribonucleocapsids. Moreover, recent findings show that hantavirus glycoproteins accomplish important roles during virus budding since they self-assemble into virus-like particles. Collectively, these novel insights provide essential information for gaining a more detailed understanding of Gn and Gc functions in the early and late steps of the hantavirus infection cycle.

The Bunyaviridae is the largest family of RNA viruses, with over 350 members worldwide. Several of these viruses cause severe diseases in livestock and humans. With an increasing number and frequency of outbreaks, bunyaviruses represent a growing threat to public health and agricultural productivity globally. Yet, the receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely uncharacterized. The focus of this review is on the early steps of bunyavirus infection, from virus binding to penetration from endosomes. We address current knowledge and advances for members from each genus in the Bunyaviridae family regarding virus receptors, uptake, intracellular trafficking and fusion.

In April 2023, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by one new family, 14 new genera, and 140 new species. Two genera and 538 species were renamed. One species was moved, and four were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

In March 2022, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by two new families (bunyaviral Discoviridae and Tulasviridae), 41 new genera, and 98 new species. Three hundred forty-nine species were renamed and/or moved. The accidentally misspelled names of seven species were corrected. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.