A conserved alpha-herpesvirus protein necessary for axonal localization of viral membrane proteins.
Pseudorabies virus, an alpha-herpesvirus, is capable of infecting the nervous system and spreading between synaptically connected neurons in diverse hosts. At least three viral membrane proteins (gE, gI, and Us9) are necessary for the spread of infection from presynaptic to postsynaptic neurons (anterograde spread) in infected rodents. To understand how these proteins effect anterograde spread between neurons, we analyzed the subcellular localization of viral proteins after infection of cultured rat sympathetic neurons with wild-type or mutant viruses. After Us9-null mutant infections but not gE-null mutant infections, only a subset of the viral structural proteins had entered axons. Surprisingly, capsid and tegument proteins but not viral membrane proteins were detected in axons. The spread of Us9 missense mutants in the rodent nervous system correlated with the amount of viral membrane proteins localized to axons. We conclude that the Us9 membrane protein controls axonal localization of diverse viral membrane proteins but not that of capsid or tegument proteins. The data support a model where virion subassemblies but not complete virions are transported in the axon. Our results provide new insight into the process of virion assembly and exit from neurons that leads to directional spread of herpesviruses in the nervous system.
Tomishima
M J
MJ
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Enquist
L W
LW
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000821:virology*; D002460:Cell Line; D016764:Cell Polarity; D017124:Conserved Sequence; D011558:Herpesvirus 1, Suid / Q000254:growth & development*; D047908:Intracellular Signaling Peptides and Proteins; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000821:virology; D013552:Swine; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014764:Viral Proteins
D047908:Intracellular Signaling Peptides and Proteins; D008074:Lipoproteins; D010750:Phosphoproteins; C491630:US9 protein, Suid herpesvirus 1; D014763:Viral Matrix Proteins; D014764:Viral Proteins