First report of heterologous expression of the tentative glycoproteins from Brevipalpus-transmitted viruses in arthropod cells

Glycoproteins and lipids are the components of viral envelopes. Brevipalpus-transmitted viruses (BTV) of the genera Cilevirus and Higrevirus (family Kitaviridae) are enveloped. Genes p61 and p65 code for tentative glycoproteins (TG) in cile- and higre-viruses, respectively. BTV of the genus Dichorhavirus (family Rhabdoviridae) are considered non-enveloped, but encode canonical G proteins as other rhabdoviruses. However, there is a lack of information on the TG biochemical properties. To study these TG and their role in forming the structure of BTVs, the genes p61 from the cilevirus citrus leprosis virus C and, G of the dichorhavirus clerodendrum chlorotic spot virus, were engineered to express them as 6XHis tagged-proteins in Spodoptera frugiperda (Sf9) cells. The protein expression was evaluated by dot blot and western blot assays using α-HIS-tag antibodies and viral TGs were purified by Ni+-NTA affinity chromatography. TGs are 60-65 KDa, and 72 hours post-infection was the best harvest time regarding quantity/ stability. After the lysis with RIPA buffer (1 hour at 4°C), TGs were recovered from the soluble fraction. Each purified TG was concentrated, dialyzed, and used to prepare specific anti-P61 and anti-G antisera. Specific antibodies will be used to study the involvement of these TG in virions, hosts, and vectors.

Keywords : CiLV-C; ClCSV; Cilevirus; Kitaviridae; Dichorhavirus; Rhabdoviridae.

Financial support : FAPESP (2017/50334-3, 2019/25078-9, and 2023/09518-4).