Rabies is a major zoonotic disease that causes approximately 55,000 human deaths worldwide on an annual basis. The nucleocapsid protein and glycoprotein genes of the Korean rabies virus (RABV) have been subjected to molecular and phylogenetic analyses. Although the phosphoprotein (P) has several important functions in viral infection and pathogenicity, the genetic characterizations of the P of Korean RABV isolates have not yet been established. In the present study, we conducted genetic analyses of P genes of 24 RABV isolates circulating in the Republic of Korea (hereafter, Korea) from 2008 to 2011. This study revealed that the P genes of Korean RABVs are genetically similar to those of RABV strains of lyssavirus genotype I including V739 (dogs, Korea), NNV-RAB-H (humans, India), NeiMeng925 (raccoon dogs, China), and RU9.RD (raccoon dogs, Russia). Among Korean isolates, the RABV P genes showed low variability in the variable domains among Korean isolates; they had specific consensus sequences and amino acid substitutions capable of identifying geographic characteristics and retained specific sequences thought to be important for viral function. These results provide important genetic characteristics and epidemiological information pertaining to the P gene of the Korean RABV.

Rabies virus (RV) is highly neurotropic and migrates to the neuronal soma by retrograde axonal transport from nerve terminals, after which it is taken by anterograde axonal transport to be finally released into the central nervous system (CNS) from which it disseminates, resulting in lethal encephalitis. Dorsal root ganglia (DRG) are crucial in the initial events of the infection by RV since they can act as a gate for the viral entrance into the CNS. In the present study, we examined cell tropism of RV and the roles of neuronal cytoskeletal components in the production of viral nucleoprotein (N protein) using cultured nerve cells and non-neuronal cells from DRG of newborn mice. Our in vitro study demonstrated a low propagation rate of RV in nerve cells, susceptibility of non-neuronal cells to RV, and independence of cytoplasmic synthesis of viral N protein from the neuronal cytoskeleton. The present study also suggests that Schwann cells should be considered as another possible candidate supporting RV propagation.