Targeting of glycoprotein I (gE) of varicella-zoster virus to the trans-Golgi network by an AYRV sequence and an acidic amino acid-rich patch in the cytosolic domain of the molecule.

ABSTRACT Varicella-zoster virus (VZV) is enveloped in thetrans-Golgi network (TGN). Here we report that glycoprotein I (gI) is required within the TGN for VZV envelopment. Enveloping membranous TGN cisternae were microscopically identified in cells infected with intact VZV. These sacs curved around, and ultimately enclosed, nucleocapsids. Tegument coated the concave face of these sacs, which formed the viral envelope, but the convex surface was tegument-free. TGN cisternae of cells infected with VZV mutants lacking gI (gIΔ) or its C (gIΔC)- or N-terminal (gIΔN)-terminal domains were uniformly tegument coated and adhered to one another, forming bizarre membranous stacks. Viral envelopment was compromised, and no virions were delivered to post-Golgi structures. The TGN was not gI-immunoreactive in cells infected with the gIΔ or gIΔNmutants, but it was in cells infected with gIΔC (because the ectodomains of gI and gE interact). The presence in the TGN of gI lacking a C-terminal domain, therefore, was not sufficient to maintain enveloping cisternae. In cells infected with intact VZV or with gIΔ, gIΔN, or gIΔC mutants, ORF10p immunoreactivity was concentrated on the cytosolic face of TGN membranes, suggesting that it interacts with the cytosolic domains of glycoproteins. Because of the gE-gI interaction, cotransfected cells that expressed gE or gI were able to target truncated forms of the other to the TGN. Our data suggest that the C-terminal domain of gI is required to segregate viral and cellular proteins in enveloping TGN cisternae.

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Varicella-Zoster Virus Glycoprotein I Is Essential for Spread in Dorsal Root Ganglia and Facilitates Axonal Localization of Structural Virion Components in Neuronal Cultures

Journal of Virology ◽

10.1128/jvi.02293-13 ◽

2013 ◽

Vol 87 (24) ◽

pp. 13719-13728 ◽

Cited By ~ 3

Author(s):

J. Christensen ◽

M. Steain ◽

B. Slobedman ◽

A. Abendroth

Keyword(s):

Varicella Zoster Virus ◽

Dorsal Root Ganglia ◽

Dorsal Root ◽

Neuronal Cultures ◽

Varicella Zoster ◽

Virus Glycoprotein ◽

Glycoprotein I

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Lysosomal Hydrolase Mannose 6-Phosphate Uncovering Enzyme Resides in the trans-Golgi Network

Molecular Biology of the Cell ◽

10.1091/mbc.12.6.1623 ◽

2001 ◽

Vol 12 (6) ◽

pp. 1623-1631 ◽

Cited By ~ 60

Author(s):

Jack Rohrer ◽

Rosalind Kornfeld

Keyword(s):

Plasma Membrane ◽

Fluorescent Protein ◽

Lysosomal Hydrolases ◽

Intracellular Location ◽

Trans Golgi Network ◽

Cytosolic Domain ◽

Cytosolic Domains ◽

Mannose 6 Phosphate ◽

Green Fluorescent ◽

Golgi Network

A crucial step in lysosomal biogenesis is catalyzed by “uncovering” enzyme (UCE), which removes a coveringN-acetylglucosamine from the mannose 6-phosphate (Man-6-P) recognition marker on lysosomal hydrolases. This study shows that UCE resides in the trans-Golgi network (TGN) and cycles between the TGN and plasma membrane. The cytosolic domain of UCE contains two potential endocytosis motifs: 488YHPL and C-terminal 511NPFKD. YHPL is shown to be the more potent of the two in retrieval of UCE from the plasma membrane. A green-fluorescent protein-UCE transmembrane-cytosolic domain fusion protein colocalizes with TGN 46, as does endogenous UCE in HeLa cells, showing that the transmembrane and cytosolic domains determine intracellular location. These data imply that the Man-6-P recognition marker is formed in the TGN, the compartment where Man-6-P receptors bind cargo and are packaged into clathrin-coated vesicles.

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Role of the Varicella-Zoster Virus gB Cytoplasmic Domain in gB Transport and Viral Egress

Journal of Virology ◽

10.1128/jvi.76.2.591-599.2002 ◽

2002 ◽

Vol 76 (2) ◽

pp. 591-599 ◽

Cited By ~ 31

Author(s):

Thomas C. Heineman ◽

Susan L. Hall

Keyword(s):

Amino Acids ◽

Plasma Membrane ◽

Amino Acid ◽

Varicella Zoster Virus ◽

Cultured Cells ◽

Signal Sequence ◽

Cytoplasmic Domain ◽

Varicella Zoster ◽

Golgi Transport ◽

Viral Egress

ABSTRACT To study the function of the varicella-zoster virus (VZV) gB cytoplasmic domain during viral infection, we produced a VZV recombinant virus that expresses a truncated form of gB lacking the C-terminal 36 amino acids of its cytoplasmic domain (VZV gB-36). VZV gB-36 replicates in noncomplementing cells and grows at a rate similar to that of native VZV. However, cells infected with VZVgB-36 form extensive syncytia compared to the relatively small syncytia formed during native VZV infection. In addition, electron microscopy shows that very little virus is present on the surfaces of cells infected with VZV gB-36, while cells infected with native VZV exhibit abundant virions on the cell surface. The C-terminal 36 amino acids of the gB cytoplasmic domain have been shown in transfection-based experiments to contain both an endoplasmic reticulum-to-Golgi transport signal (the C-terminal 17 amino acids) and a consensus YXXφ (where Y is tyrosine, X is any amino acid, and φ is any bulky hydrophobic amino acid) signal sequence (YSRV) that mediates the internalization of gB from the plasma membrane. As predicted based on these data, gB-36 expressed during the infection of cultured cells is transported inefficiently to the Golgi. Despite lacking the YSRV signal sequence, gB-36 is internalized from the plasma membrane; however, in contrast to native gB, it fails to localize to the Golgi. Therefore, the C-terminal 36 amino acids of the VZV gB cytoplasmic domain are required for normal viral egress and for both the pre- and post-Golgi transport of gB.

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