This family consists of several Tenuivirus and Phlebovirus nucleocapsid proteins [1,2]. These are ssRNA viruses. In crystal structures the nucleocapsid protein from the Rift Valley fever virus (RVFV) displays a ring-shaped oligomeric assembly [3,4]. Electron microscopy (EM) also demonstrates that, in complex with RNA, the RVFV nucleocapsid protein forms rings in solution [4].

1: Nucleotide sequence and RNA hybridization analyses reveal an ambisense coding strategy for maize stripe virus RNA3. Huiet L, Klaassen V, Tsai JH, Falk BW; Virology 1991;182:47-53. PMID:2024478

2: Sequences and coding strategies of the S RNAs of Toscana and Rift Valley fever viruses compared to those of Punta Toro, Sicilian Sandfly fever, and Uukuniemi viruses. Giorgi C, Accardi L, Nicoletti L, Gro MC, Takehara K, Hilditch C, Morikawa S, Bishop DH; Virology 1991;180:738-753. PMID:1846496

3: Structure of the Rift Valley fever virus nucleocapsid protein reveals another architecture for RNA encapsidation. Raymond DD, Piper ME, Gerrard SR, Smith JL; Proc Natl Acad Sci U S A. 2010;107:11769-11774. PMID:20547879

4: The hexamer structure of Rift Valley fever virus nucleoprotein suggests a mechanism for its assembly into ribonucleoprotein complexes. Ferron F, Li Z, Danek EI, Luo D, Wong Y, Coutard B, Lantez V, Charrel R, Canard B, Walz T, Lescar J; PLoS Pathog. 2011;7:e1002030. PMID:21589902