Rift Valley fever virus p78 protein (p78)

The Rift Valley fever virus (RVFV) p78 protein is a 78-kDa accessory glycoprotein encoded by the M segment of the virus's tripartite RNA genome (UniProt P03518). It is synthesized via alternative translation initiation from the first of five in-frame AUG codons, resulting in a fusion of the NSm and Gn protein sequences (Won et al., 2006). The p78 protein is primarily recognized for its critical role in the mosquito vector, where it is essential for virus dissemination from the midgut to other tissues, thereby facilitating transmission to vertebrate hosts (Kreher et al., 2014). In mammalian systems, p78 is typically expressed at low levels and is not required for viral replication; however, experimental overexpression has been shown to attenuate viral virulence by reducing replication efficiency in macrophages (Terasaki et al., 2021). The protein is incorporated into the viral envelope of virions produced in insect cells but is largely absent from those produced in mammalian cells, suggesting a specialized role in the arthropod phase of the viral life cycle (UniProt P03518). Although p78 is not currently a target for any approved therapeutics, its role in host-vector interactions and its potential for use in developing live-attenuated vaccines make it a significant focus of RVFV research (Terasaki et al., 2021).

Other names

NSm-Gn proteinLGp78 kDa proteinp78/NSm-GnM polyprotein (cleaved into p78)

No drugs are currently known to target the Rift Valley fever virus p78 protein; thus, no clinical mechanism of action has been defined.