Alan Keith Robbins

Two α-herpesvirus strains are transported differentially in the rodent visual system

Abstract Uptake and transneuronal passage of wild-type and attenuated strains of a swine α-herpesvirus (pseudorabies [PRV]) were examined in rat visual projections. Both strains of virus infected subpopulations of retinal ganglion cells and passed transneuronally to infect retinorecipient neurons in the forebrain. However, the location of infected forebrain neurons varied with the strain of virus. Intravitreal injection of wild-type virus produced two temporally separated waves of infection that eventually reached all known retino-recipient regions of the central neuraxis. By contrast, the attenuated strain of PRV selectively infected a functionally distinct subset of retinal ganglion cells with restricted central projections. The data indicate that projection-specific groups of ganglion cells are differentially susceptible to the two strains of virus and suggest that this sensitivity may be receptor mediated.

Overall signal sequence hydrophobicity determines the in vivo translocation efficiency of a herpesvirus glycoprotein

We have described three mutant strains of Pseudorabies virus that contain mutations in the signal sequence coding region of a nonessential envelope glycoprotein, gIII. The alterations disrupt, truncate, or eliminate the hydrophobic core domain of the signal sequence. Each mutant was assayed for its ability to promote the translocation of gIII across the endoplasmic reticulum membrane and the subsequent localization of the mature form of the glycoprotein to the infected cell surface or the virus envelope. Our results confirm and extend findings in other systems that the overall hydrophobicity of the signal sequence core region is a major determinant of translocation efficiency. We were unable to correlate simply the length of the core or the average hydrophobicity of core residues with export efficiency. Because our work involved the use of infectious virus mutants, we were able to identify a virus defect associated with a complete block in gIII export. This defect will facilitate a pseudoreversion analysis of gIII signal sequence function.