Functions of the internal pre-S domain of the large surface protein in hepatitis B virus particle morphogenesis

Bruss, Volker; Vieluf, K

doi:10.1128/jvi.69.11.6652-6657.1995

Cited by 100 publications

(44 citation statements)

References 33 publications

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“…Previous studies based on cell transfection with HBV mutants for the L protein suggested that it is retained in the ER as a transmembrane protein because of binding to a cytosolic factor. 16 In a recent study, the L protein alone was found to form intravesicular 20-nm spherical particles identical to the S and M protein particles but retained in intracellular compartments by calnexin. 17 Nevertheless, the so-called ground-glass appearance of the hepatocytes in chronic HBV infection seems to be caused by the intracellular accumulation of L-protein-rich filaments.…”

Section: Discussionmentioning

confidence: 95%

Ultrastructural analysis of hepatitis B virus in HepG2-transfected cells with special emphasis on subviral filament morphogenesis

Roingeard

Sureau

1998

Hepatology

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The intracellular accumulation of empty hepatitis B virus (HBV) particles of filamentous shape leads to a direct cytopathic effect in so-called ground-glass hepatocytes. The aim of this study was to investigate how these filaments can be structurally formed at the cellular level. By electron microscopy, we reexamined the HBV-producer HepG2T-14 cells, which have been described as producing a substantial amount of empty HBV filaments compared with the other forms of HBV particles. Examination of ultrathin sections of HepG2T14 cells revealed the presence of HBV virions and filaments at the periphery of extremely large intracellular cisternae, probably related to a pre-Golgi compartment. Very long filaments appeared to be formed by a tubular budding of a long portion of the cisterna membrane. This phenomenon may be identical to that observed in the hepatocytes of HBV chronic carriers, in which the inability of the infected cell to export long HBV filamentous particles through the cellular secretion pathway seems to be at the origin of a direct cytopathic effect. (HEPATOLOGY 1998;28: 1128-1133.)Hepatitis B virus (HBV) is an enveloped hepatotropic DNA virus that infects a large number of people worldwide. 1 Its genome is encapsulated with a virus-encoded polymerase in a nucleocapsid surrounded by a host-derived lipid envelope bearing three viral surface proteins. 2 The large (L) protein, containing the preS1, preS2, and S domains, is translated from the first start codon of the surface open reading frame. The middle (M) protein, containing the preS2 and S domain, and the small (S) protein are translated from in-frame start codons further downstream. 2 During synthesis, all three proteins are cotranslationally inserted into the endoplasmic reticulum (ER) as transmembrane proteins that can form disulfide bridges with each other. 3 The S protein traverses the ER membrane at least twice to form a cytosolic loop and a luminal domain. 4 The M protein has a similar topology with the additional N-terminal preS2 domain located in the ER lumen. 5 The L protein can adopt two different transmembrane topologies, allowing the exposure of the N-terminal preS domain at either the luminal or the cytosolic side of the ER membrane. 6 This latter form is essential during HBV morphogenesis to establish a protein-protein interaction between the cytoplasmic core particle and a specific sequence within the preS domain of the L protein. 7,8 One peculiarity of HBV morphogenesis compared with that of other viruses is that the surface proteins not only envelop the nucleocapsid to form a mature virion, they are capable of forming subviral empty spherical or filamentous particles in the absence of nucleocapsid. 2 Although the envelopes of all types of HBV particles contain the M and S proteins, filamentous and virion envelopes are richer in the L protein. 2 It is thought that during morphogenesis, the M and S proteins, in the absence of any other viral proteins, can bud into a post-ER/pre-Golgi compartment to form 20-nm spherical particles that ca...

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Section: Discussionmentioning

confidence: 95%

Ultrastructural analysis of hepatitis B virus in HepG2-transfected cells with special emphasis on subviral filament morphogenesis

Roingeard

Sureau

1998

Hepatology

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“…The pre-S domain has been shown to be necessary for viral budding at the ER. 16 Despite this complex configuration of the pre-S region, mutations including deletion and insertion are found frequently in chronic HBV carriers. 18,[27][28][29] The selection pressure resulting in pre-S mutations is not as obvious for mutations found in the ''a'' determinant of the S-gene.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it is necessary that the pre-S domain passes through the membrane, and in the mature virion, half of the pre-S domains are located either inside or outside of the viral envelope. 16,17 The complex function of the pre-S domain and the different levels of regulation indicate that the virus uses this small region very efficiently. However, naturally occurring mutants in the pre-S region are found frequently, and they seem to correlate with a more progressive form of liver disease (Locarnini S, McMillan J, personal communication, November, 1998).…”

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confidence: 99%

The Pre-S region determines the intracellular localization and appearance of hepatitis B virus

et al. 1999

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The functional role of the hepatitis B virus (HBV) pre-S region for assembly and appearance of the virus is not completely understood. In this study, 3 natural-occurring mutants were investigated. Three mutants of the pre-S region-a point mutation in the CCAAT box (MUT1), a 6-bp deletion (MUT2) 3Ј of the CCAAT box, and a 153-bp deletion (MUT3) in the preS2 domain-were cloned alone or in combinations in replication-competent HBV plasmids and transfected in hepatoma cells. The impact on HBV assembly and appearance was studied by Northern Blot, primer extension analysis, immunofluorescence studies, enzyme-linked immunosorbent assay, and electron microscopy. An inversed ratio of pre-S/S mRNA transcripts compared with wild-type (wt) HBV was found when either MUT1 or -2 were included into the plasmid. Intracellular localization with both mutants showed retention of large S-protein in the endoplasmic reticulum and nuclear accumulation of core protein. The extracellular amount of S-protein was reduced with MUT1 and -2 or combinations in which 1 of the mutants was included. However, the extracellular appearance of viral products was comparable with wtHBV. In contrast, MUT3 showed major changes. Virion-like particles had a fried-egg, and filaments a screw-like appearance. The S-promoter mutations MUT1 and MUT2 correlated with viral retention. MUT3 leads to malformed viral particles. Therefore, different regions in the pre-S domain are essential to determine the intracellular localization and extracellular appearance of HBV, and might contribute to the prognosis of chronic HBV infection. (HEPATOLOGY 1999; 30:517-525.)The hepatitis B virus (HBV) is the smallest DNA virus known to be pathogenic for humans. The HBV is a member of the hepadnavirus family, showing a close host tropism. The genome of the HBV consists of a small circular DNA of 3.2 kb in length. Despite its small size, the HBV genome contains 4 open reading frames partly overlapping and generating at least 7 viral gene products. The 4 open reading frames are under the transcriptional control of 4 promoters (preS1, S, C, and X promoter) and 2 enhancer (enhancer I and II) elements. [1][2][3] The envelope gene of the HBV is controlled by 2 different promoters: the pre-S-and the S-promoter, which regulate transcription of a 2.4-and a 2.1-kb mRNA, respectively. The pre-S-promoter is located 5Ј of the first in frame ATG of the large (pre-S1) envelope protein. The S-promoter is found in the coding region of the pre-S gene and is a TATA-less promoter. Mainly, 2 factors control the activity of the Spromoter: Sp 1 and NF-Y. 4-7 NF-Y binds to the so-called CCAAT box and is especially important for the regulation of the S-gene controlling the ratio between the pre-S and S mRNA. 4,8 The 2 mRNAs transcribed from the S-gene code for 3 S-proteins (small, middle, and large) sharing the 226 amino acids at the C-terminus. Translation of the small S-protein starts at the third in-frame ATG of the S-gene, while the other 2 proteins start at the first and second ATG. However, some sub...

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“…Unlike some Lentivirinae able to bud through a lipid bilayer without any envelope protein (Hourioux et al, 2000), the HBV nucleocapsid budding is strictly dependent on the large L protein. The absence of L or its in vitro production under an exclusive 'e-preS' topology completely abolish the generation of new virions (Bruss and Vieluf, 1995). Indeed, the 'i-preS' topology of L is obligatory for mature HBV nucleocapsid recruitment.…”

Section: Hbv Morphogenesismentioning

confidence: 99%

Morphogenesis of hepatitis B virus and its subviral envelope particles

Patient¹,

Hourioux

Roingeard³

2009

Cellular Microbiology

134

136

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SummaryAfter cell hijacking and intracellular amplification, non-lytic enveloped viruses are usually released from the infected cell by budding across internal membranes or through the plasma membrane. The enveloped human hepatitis B virus (HBV) is an example of virus using an intracellular compartment to form new virions. Four decades after its discovery, HBV is still the primary cause of death by cancer due to a viral infection worldwide. Despite numerous studies on HBV genome replication little is known about its morphogenesis process. In addition to viral neogenesis, the HBV envelope proteins have the capability without any other viral component to form empty subviral envelope particles (SVPs), which are secreted into the blood of infected patients. A better knowledge of this process may be critical for future antiviral strategies. Previous studies have speculated that the morphogenesis of HBV and its SVPs occur through the same mechanisms. However, recent data clearly suggest that two different processes, including constitutive Golgi pathway or cellular machinery that generates internal vesicles of multivesicular bodies (MVB), independently form these two viral entities.

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Functions of the internal pre-S domain of the large surface protein in hepatitis B virus particle morphogenesis

Cited by 100 publications

References 33 publications

Ultrastructural analysis of hepatitis B virus in HepG2-transfected cells with special emphasis on subviral filament morphogenesis

Ultrastructural analysis of hepatitis B virus in HepG2-transfected cells with special emphasis on subviral filament morphogenesis

The Pre-S region determines the intracellular localization and appearance of hepatitis B virus

Morphogenesis of hepatitis B virus and its subviral envelope particles

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