Human Cytomegalovirus morphogenesis: an ultrastructural study of the late cytoplasmic phases

Severi, B.; Landini, Maria Paola; Govoni, E

doi:10.1007/bf01321005

Cited by 76 publications

(78 citation statements)

References 49 publications

(52 reference statements)

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“…3B) showed that SNAP-23 was spread through the cytoplasm in mock-infected cells, presumably owing to its association with vimentin filaments (29). In contrast, at 96 hpi, a substantial portion of SNAP-23 colocalized with pUL99 and pUL55 (gB), markers for the HCMV assembly compartment, the site at which the virion acquires an envelope (9)(10)(11)(12).…”

Section: Virion Glycerophospholipid Composition Is Different From Thamentioning

confidence: 99%

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Synaptic vesicle-like lipidome of human cytomegalovirus virions reveals a role for SNARE machinery in virion egress

Liu¹,

Sharon-Friling²,

Ivanova

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Human cytomegalovirus induces and requires fatty acid synthesis. This suggests an essential role for lipidome remodeling in viral replication. We used mass spectrometry to quantify glycerophospholipids in mock-infected and virus-infected fibroblasts, as well as in virions. Although the lipid composition of mock-infected and virus-infected fibroblasts was similar, virions were markedly different. The virion envelope contained twofold more phosphatidylethanolamines and threefold less phosphatidylserines than the host cell. This indicates that the virus buds from a membrane with a different lipid composition from the host cell as a whole. Compared with published datasets, the virion envelope showed the greatest similarity to the synaptic vesicle lipidome. Synaptosomeassociated protein of 25 kDa (SNAP-25) is a component of the complex that mediates exocytosis of synaptic vesicles in neurons; and its homolog, SNAP-23, functions in exocytosis in many other cell types. Infection induced the relocation of SNAP-23 to the cytoplasmic viral assembly zone, and knockdown of SNAP-23 inhibited the production of virus. We propose that cytomegalovirus capsids acquire their envelope by budding into vesicles with a lipid composition similar to that of synaptic vesicles, which subsequently fuse with the plasma membrane to release virions from the cell.H uman cytomegalovirus (HCMV) is a member of the enveloped herpesvirus family. It is a widespread pathogen that can cause disease in immunologically immature or compromised individuals (1). HCMV infection substantially alters the metabolism of cultured fibroblasts (2), inducing a marked increase in the flux of carbon from glucose into fatty acids (3). Consistent with the enhanced flux, inhibition of acetyl-CoA carboxylase, the first committed enzyme in the fatty acid biosynthetic pathway, reduces the yield of infectious virus. Thus, lipid synthesis is required during the HCMV replication cycle. Newly synthesized membranes likely accumulate in the assembly compartment (4-8), a virus-induced organelle with virus-coded proteins and cellular proteins that include markers of the exocytic and endocytic networks. This is the site at which viral capsids acquire an envelope (9-12).Glycerophospholipids are major components of cellular membranes. This family of lipids consists of a glycerol backbone, a functional head group, and two fatty acids of varying length and unsaturation. Phosphatidic acid (PA) serves as the basic glycerophospholipid building block, with its phosphate group esterified to a head group to produce phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylglycerol (PG), or diphosphatidylglycerol. By using mass spectrometry, it is possible to identify and quantify numerous glycerolphospholipid species, differing in head group, acyl chain length, and degree of unsaturation (13-16). This quantitative lipidomics approach has been used to generate detailed descriptions of several viral envelopes, including those acqui...

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Section: Virion Glycerophospholipid Composition Is Different From Thamentioning

confidence: 99%

“…Newly synthesized membranes likely accumulate in the assembly compartment (4)(5)(6)(7)(8), a virus-induced organelle with virus-coded proteins and cellular proteins that include markers of the exocytic and endocytic networks. This is the site at which viral capsids acquire an envelope (9)(10)(11)(12).…”

mentioning

confidence: 99%

Synaptic vesicle-like lipidome of human cytomegalovirus virions reveals a role for SNARE machinery in virion egress

Liu¹,

Sharon-Friling²,

Ivanova

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…The late cytopathic effect in the cytoplasm is characterized by a rearrangement of the Golgi complex and accumulation of membrane cisternae and viral particles in the vicinity of the centrosome, referred to as the viroplasm (Severi et al, 1988). At that stage, envelopment of progeny is seen to occur in association with the tubular endosome which was visualized by uptake of fluid phase marker HRP (Fig.…”

Section: Maturation Of Cytoplasmic Progeny Virions Is Blocked In Ul32mentioning

confidence: 99%

Human cytomegalovirus late-phase maturation is blocked by stably expressed UL32 antisense mRNA in astrocytoma cells.

Meyer¹,

Ripalti

Landini³

et al. 1997

Journal of General Virology

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Human cytomegalovirus (HCMV) open reading frame UL32 codes for the basic phosphoprotein pp150 (ppUL32), an abundant constituent of the virion tegument. In order to study its potential role in the assembly and/or transport of progeny particles, astrocytoma cell lines (U373MG) were generated, stably expressing a 2n1 kb 5h fragment of UL32 in antisense orientation under the control of the HCMV major immediate early promoter. The steady-state level of the UL32 sense mRNA and pp150 synthesis were strongly reduced in infected antisense cell lines. Neither immediate early and early gene expression, nor viral DNA replication, was inhibited ; the expression of the late gene product gB (gpUL55) was also reduced, but mainly at the level of translation. Control experiments indicated that this dif-

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“…could represent incorporation of a virally modified normal cell component during particle assembly. Envelopment of CMV nucleocapsids was originally thought to occur at the internal nuclear membrane (Smith & de Harven, 1973), but recent electron microscopic studies favour acquisition of the final envelope in the Golgi apparatus region of infected cells (Severi et al, 1988) and occasionally at the plasma membrane (Landini et al, 1987). It is therefore plausible that during envelopment, both virally modified and unmodified normal membrane constituents are incorporated into the viral envelope.…”

Section: K--mentioning

confidence: 99%

A Human Cytomegalovirus-neutralizing Monoclonal Antibody Recognizes a Normal Cell Protein

Michelson

Tardy-Panit

Colimon

et al. 1989

Journal of General Virology

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SUMMARYA monoclonal antibody (MAb), N2, neutralized human cytomegalovirus (HCMV) infectivity in the absence of complement and recognized a normal cell protein. By immunofluorescence, MAb N2 detected antigens in uninfected human cells, but not in cells of non-human origin. Antigens were present at the membrane and were dispersed diffusely within the cytoplasm. MAb N2 immunoprecipitated a glycoprotein with an M r of 94K from uninfected and infected cells. In infected cells only, it also recognized a protein of Mr 34K which was not linked to the 94K Mr glycoprotein by disulphide bonds. N2 neutralized both laboratory and field isolates of HCMV. A study of the distribution of the N2 neutralization epitope recognized among fresh isolates of HCMV showed that only 67~ of the isolates could be neutralized by this antibody. There was no correlation between the number of in vitro passages and the level of neutralization. The 34K Mr polypeptide was present in cells infected by all isolates. It thus appears that, during virus assembly, HCMV acquires a normal cell protein that bears a neutralization epitope.

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Human Cytomegalovirus morphogenesis: an ultrastructural study of the late cytoplasmic phases

Cited by 76 publications

References 49 publications

Synaptic vesicle-like lipidome of human cytomegalovirus virions reveals a role for SNARE machinery in virion egress

Synaptic vesicle-like lipidome of human cytomegalovirus virions reveals a role for SNARE machinery in virion egress

Human cytomegalovirus late-phase maturation is blocked by stably expressed UL32 antisense mRNA in astrocytoma cells.

A Human Cytomegalovirus-neutralizing Monoclonal Antibody Recognizes a Normal Cell Protein

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