|Home | About | Journals | Submit | Contact Us | Français|
Marine mammals suffer from a variety of poorly understood immunosuppressive and neoplastic disorders, yet little is known about putative infectious agents. LaMere et al. (p. 12956-12967) have identified and characterized the first gammaretrovirus in killer whales. While current evidence defines this retrovirus as endogenous and clinical consequences of infection have not been reported, the viral genome was relatively intact, and viral homologs were found in all delphinid species studied. This work reveals that retroviral infections do not stop at the shore and may extend throughout the mammalian fauna of the ocean with potential significance to the health of these threatened populations.
The flavivirus NS3 protein is a bifunctional enzyme with serine protease and RNA helicase activities. Both activities are essential to flavivirus replication, which makes NS3 an attractive target for antiviral therapy. Assenberg et al. (p. 12895-12906) reveal a novel conformational state of the NS3 protein in which the protease and helicase domains are segregated by a flexible linker. Comparative analysis suggests that the linker allows the two domains to move relative to each other with considerable freedom. These observations suggest that significant plasticity of the NS3 protein is crucial for the membrane-associated activity of NS3 in vivo.
The UL17 and UL25 proteins of herpes simplex virus 1 likely bridge capsid pentonic vertices and neighboring hexons. Scholtes and Baines (p. 12725-12737) now show that the UL17 and UL25 proteins (pUL17 and pUL25, respectively) directly interact. This interaction, as well as the nuclear localization, solubility, and immunoreactivity of pUL17 and pUL25, is enhanced by the corresponding interaction partner, major components of the capsid shell, and UL32 protein, which plays an essential but previously enigmatic role in DNA packaging. These results demonstrate multiple unanticipated functions that optimize the association of pUL17/pUL25 with capsids.
Recent technical advances have made it possible to determine the number of viral epitope-specific CD8+ T cells in immunologically naïve mice. Seedhom et al. (p. 12907-12916) describe an in vivo limiting dilution assay to calculate the number of T cells specific for entire viruses without requiring knowledge of any viral epitopes. Using this assay, the authors found high numbers of virus-specific T cells in naïve mice, with frequencies of 1 in 1,444 and 1 in 2,958 for vaccinia virus (VV) and lymphocytic choriomeningitis virus, respectively. This assay also revealed nearly 100-fold increases in VV-specific T cells in VV-immune mice.
White root rot, caused by the ascomycete Rosellinia necatrix, is a devastating disease worldwide, particularly in fruit trees in Japan. Chiba et al. (p. 12801-12812) describe the biological and molecular properties of a novel bipartite double-stranded RNA virus infecting R. necatrix, which may belong to a new virus family. A transfection protocol using purified virions showed that the virus causes reduction of fungal virulence and mycelial growth in the host. This work will serve as a solid foundation for the development of virocontrol measures to limit white root rot disease and enable future studies of virus-host interactions.