Journal of Virology, November 2009, p. 11415, Vol. 83, No. 22
0022-538X/09/$08.00+0 doi:10.1128/JVI.02001-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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Articles of Significant Interest Selected from This Issue by the Editors
Limited Information Favors Deterministic Lysis-Lysogeny Choice in Phage LambdaPhage lambda makes lysis-lysogeny decisions based on the multiplicity of infection. Avlund et al. (p. 11416-11420) show that limited information about the environment, as is the case with a single infection, favors a strategy that optimizes proliferation of individual phages and, therefore, phages must make a deterministic choice. In contrast, multiple infections provide phages with information about the presence of other clones, whereupon long-term survival favors a stochastic choice between lysis and lysogeny. Thus, phages play dice because the existence of multiple infecting clones allow them to hedge their bets.
Endoplasmic Reticulum Chaperone BiP/GRP78 and Human Cytomegalovirus Assembly
The endoplasmic reticulum (ER) chaperone BiP/GRP78 is a key controller of the unfolded protein response. In cells infected with human cytomegalovirus (HCMV), BiP is overproduced and functions in viral assembly and egress. Buchkovich et al. (p. 11421-11428) show that during HCMV infection, some BiP is displaced from the ER to the perinuclear viral assembly compartment, where it associates with other viral proteins involved in virion assembly. BiP is critical for maintenance of the assembly compartment, since BiP depletion causes assembly compartment dissociation. These results show that HCMV utilizes a major ER chaperone for viral assembly compartment function and maintenance.
New Relatives of Influenza Virus Identified
The identity of Quaranfil virus, which was first isolated more than 50 years ago from febrile children and since then repeatedly from ticks and birds, has long been an engima. Presti et al. (p. 11599-11606) now demonstrate that Quaranfi virus, and two serologically related viruses, Johnston Atoll and Lake Chad viruses, are members of the Orthomyxoviridae. These viruses are highly divergent from known orthomyxoviruses, and phylogenetic analysis suggests that they define a new genus in this family. This work will enable studies to assess whether Quaranfil virus is a human pathogen and foster development of new models of orthomyxovirus disease.
Retrotransposon Nuclear Entry Requirement for GLFG Nucleoporins
Ty3 is a long terminal repeat retrotransposon in budding yeast. Beliakova-Bethell et al. (p. 11914-11925) show that Ty3 structural protein Gag3 interacts with the GLFG class of nucleoporins and that GLFG repeats are required for late stages of retrotransposition. A two-step model of nuclear entry is proposed. Ty3 first docks on nuclear pores via interaction of Gag3 with GLFG repeats. The docked particle uncoats, thereby exposing auxiliary nuclear entry signals that further facilitate nuclear entry. A similar system may be exploited by animal retroviruses that enter nondividing cells in which the nuclear envelope remains intact.
Basis for High-Level Replication of Hepatitis C Virus
Analysis of the hepatitis C virus (HCV) replication cycle in cell culture is currently limited to a single viral isolate, JFH1. Simister et al. (p. 11926-11939) provide evidence that the replication efficiency of the JFH1 strain is attributable to its RNA polymerase. The structure of the enzyme reveals a unique conformation that correlates with increased efficiency of RNA synthesis initiation. This work identifies a bottleneck limiting HCV replication that might be exploited to allow additional HCV isolates to be adapted to growth in cell culture.
Journal of Virology, November 2009, p. 11415, Vol. 83, No. 22
0022-538X/09/$08.00+0 doi:10.1128/JVI.02001-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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