Abstract

The human hepatitis B virus (HBV), that is causative for more than 240 million cases of chronic liver inflammation (hepatitis), is an enveloped virus with a partially double-stranded DNA genome. After virion uptake by receptor-mediated endocytosis, the viral nucleocapsid is transported towards the nuclear pore complex. In the nuclear basket, the nucleocapsid disassembles. The viral genome that is covalently linked to the viral polymerase, which harbors a bipartite NLS, is imported into the nucleus. Here, the partially double-stranded DNA genome is converted in a minichromosome-like structure, the covalently closed circular DNA (cccDNA). The DNA virus HBV replicates via a pregenomic RNA (pgRNA)-intermediate that is reverse transcribed into DNA. HBV-infected cells release apart from the infectious viral parrticle two forms of non-infectious subviral particles (spheres and filaments), which are assembled by the surface proteins but lack any capsid and nucleic acid. In addition, naked capsids are released by HBV replicating cells. Infectious viral particles and filaments are released via multivesicular bodies; spheres are secreted by the classic constitutive secretory pathway. The release of naked capsids is still not fully understood, autophagosomal processes are discussed. This review describes intracellular trafficking pathways involved in virus entry, morphogenesis and release of (sub)viral particles.

Highlights

  • The human hepatitis B virus (HBV) belongs to the family of Hepadnaviridae, a group of small hepatotropic DNA viruses

  • This review describes intracellular trafficking pathways involved in virus entry, morphogenesis and release ofviral particles

  • A recent study revealed that the release of the HBV viral particle via the ESCRT machinery is mediated by the cellular protein α-taxilin, which harbors a YXXL motive corresponding to the late domain found in Gag protein of EIAV (equine infectious anemia virus (EIAV))

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Summary

Introduction

The human hepatitis B virus (HBV) belongs to the family of Hepadnaviridae, a group of small hepatotropic DNA viruses. Due to a posttranslational nascent LHBs does not function as a co-translational translocation signal sequence, leading to the translocation, about 50% of TM1 are integrated in the ER membrane. In this case, the PreS1PreS2 cytosolic exposure of the PreS1PreS2 domain and S-domain up to aa 79. The NTD assumed to be linked by a disulfide bridge, the stem constitutes the dimer interface and exposes the consists of the first N-terminal 149 or 151 aa (depending on the genotype), which are sufficient for spikes on the outer surface of the icosahedral capsid [20,21]. Recent reports provide an excellent overview about the structure of the different types of core dimers and capsids [41,42]

Intracellular Cytoplasmic Transport after Viral Uptake
Capsid Maturation
Envelopment
Release of HBV Subviral Spheres
Release of HBV Viral Particles and Filaments
Release of Naked Capsids
Conclusions
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