Hepatitis B (HBV) Viral Important Structures Abbreviation
Heparan Sulphate Proteoglycan
HSPG
+
Human Na Taurocholate Co-Transporting
Polypeptide
Clathrin
Rab5
Rab7
Numerical Name Localization
HSPG
Plasma Membrane
NTCP
NTCP
Plasma Membrane
--Rab5
Rab7
--Rab5
Rab7
Plasma Membrane
Cytoplasm
Cytoplasm
Tubulin
---
---
Cytoplasm
Importin-β
---
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Nucleus
Polymerase K
POLK
POLK
Nucleus
Polymerase (Reverse Trancscriptase)
P, RT
P, RT
Virion Core
Nxf1/Tap
Nxf1/Tap
Nfx1/Tap
Nucleus (Shuttles In/Out to Cytoplasm)
HBV Surface Antigen
HBsAg
HBsAg
Virion Surface
HBV Core Antibody
anti-HBc
anti-HBc
Virion Core
HBV Surface Antibody
anti-HBs
anti-HBs
Virion Surface
Relaxed Circular DNA
rcDNA
rcDNA
Virion Core
Covalently Closed Circular DNA
cccDNA
cccDNA
Nucleus
Subviral Particle
SVP
SVP
Extracellular Matrix
Pre-Genomic RNA
pgRNA
pgRNA
Cytoplasm
Large Surface Protein
LHBs
LS
Plasma Membrane/MVBs
Medium Surface Protein
MHBs
MS
Plasma Membrane/MVBs
Small Surface Protein
SHBs
SS
Plasma Membrane/MVBs
Core Protein
HBe, HBc
Hbe, HBc
Virion Core
Regulatory Protein
HBx
HBx
Virion Core
Interferon-α
IFN-α
IFN-α
Cytoplasm
CHMPs
CHMPs (ESCRT-III)
CHMPs 1, 2, 4
Cytoplasm/Plasma Membrane
ALIX
ALIX
ALIX
Cytoplasm/Plasma Membrane
Direct Repeats 1 & 2
DR1, DR2
DR1, DR2
rcDNA/(-) Strand DNA
Function
Attachment Receptor for HBV; Interacts With SHBs
A Liver-Specific Bile Acid Transporter (Host Function); Serves as the Cellular
Receptor for HBV/HDV and Interacts with the PreS1 Domain of LHBs
Serves Major Role in Formation of Cellular Vesicles and Virus Endocytosis
Directs Vesicles from Plasma Membrane to Early Endosomes
Directs/Develops Early Endosomes to Late Endosomes/Endo-Lysosomes
Maintains Host Cell Structure and Provides a Platform for Intracellular Transport;
Facilitates Efficient Shuttling of HBV cccDNA to the Nucleus
A Nuclear Pore Protein that Transports the HBV Genome into the Nucleus by
Binding to a NLS on the C-Terminus of the HBc Protein; The Viral Capsid Either 1)
Disassembles Prior to Contact with Importin-β or 2) Capsid Destabilization Occurs
as Capsid Travels Through Importin-β
POLK is a Host DNA Pol that is Specifically Involved in DNA Repair; Carries Out
Translesion Synthesis to Ligate the Gaps in Viral rcDNA, Converting it into cccDNA
RDDP, DDDP, Helicase, RNaseH: Multifunctional Enzyme that Converts the Viral
pgRNA into (-) Strand ssDNA Within the Immature Capsid (Traveling Through
Cytoplasm); RT initiates Transcription at a Bulge in the pgRNA Near 5' End, Adds
3-4 NTs, 1st Strand Transfer; Translocate Synthesized NTs to DR1 Near 3' End of
pgRNA, and Continues Elongation; pgRNA is Degraded While (-) Strand ssDNA
Synthesis Takes Place; the (-) Strand DNA is Fully Synthesized and a Primer with a
DR1 Seq. for (+) Strand DNA Synthesis is Created by RNaseH Activity Through
Cleavage; Primer is Translocated From DR1 to DR2 and (+) Strand DNA is Initiated,
Elongation Continues Until P Runs Out of Template, and DNA Molecule
Circularizes; (+) Strand Anneals to 3' r of (-) Strand, Forming a Complete rcDNA
HBV genome
Mediates Nuclear Export of Host-Transcribed pgRNA; Nfx1/Tap Contains a NES
and a NLS to Continually Shuttle In/Out of the Nucleus
A Protein On the Surface of HBV virions and is Detectable in High Levels in Serum
for Both Acute and Chronic HBV Infections; Presence Indicates an Individual is
Infectious (INFECTED)
An Antibody that Appears at the Onset of Symptoms in Acute HBV Infection and
Persists for Life; Present in Both Acute and Chronic Infections (INFECTED)
An Antibody Whose Presence Usually Indicates Recovery and Immunity From
HBV Infection; anti-HBs Also Develops in Individuals Who Have Been Successfully
Vaccinated Against HBV (No Longer Infected/Vaccinated)
The Form of HBV's Small 3.2 kb Genome; It is Mostly dsDNA But Contains a
ssDNA Gap With the 5' End of its (+) Strand Attached to a Tyr Residue in the P Pol
and the 5' End of the (+) Strand Complement Joined to a Short, Capped RNA; the
(+) Strand is Shorter than the (-) Strand, Due to Interuption of its Synthesis Before
Completion (Causing the Single-Stranded Region); Both Strands are Held Together
By H-Bonding Between the Short Repeat DR2 Sequences Present at Each 5' End
rcDNA is Converted into this Covalently Closed Circular dsDNA Form: Occuring in
the Host Nucleus Either By Viral P Protein or By Host Pols Through Extension of
the (+) DNA Strand, Removal of Terminal Primers, and Covalent Ligation of the
Resulting 3' and 5' Ends of Each DNA Strand; HBV cccDNA is Not Immediately
Integrated into the Host Chromosome But Instead Remains in a Free, Circular
Form, and the Viral Genome Gets Transcribed by Host RNA Pol II Into a Set of 5
mRNAs (1 of Which Also Serves as the pgRNA)
High Concentrations of Subviral Particles Are Found in the Serum in Addition to
the Complete Dane Particles, Either in a Spherical or Filamentous Shape; Spherical
Particles Only Contain SHBs and MHBs While Filamentous Particles Also Contain
LHBs, and Neither SVP Contains Any HBc, RT, or Viral Genome DNA; It is Believed
that These SVPs Are Produced in Massive Amounts (100x-100,000x > Dane
Particles) to Provide a "Stealth" Mechanism for Evading Host Immune Response,
Causing Immune Antibodies to Bind/Complement the SVPs Instead of the LessAbundant Virions
The Pre-Genomic RNA is the mRNA Transcript that Encodes the C and P Proteins,
But it Also Serves as a Template to Produce the DNA Genome of HBV; Genome
Synthesis From pgRNA Involves a Ribonucleoprotein Complex of pgRNA With Core
and Polymerase Proteins
LHBs is the Least Abundant Surface Protein Present in the HBV Virion and its
Transcript is Exclusively Initiated From the PreS1 Promoter; Its PreS1 Domain
Binds to Host NTCP Receptors and is Myristoylated at its N-Terminus Anchor; All
HBs Are Involved in Envelope Formation and the Formation of SVPs Found in the
Serum
MHBs is HBV's 2nd-Most Abundant Surface Protein Whose Transcript is Initiated
at the S Promoter, But Contains An Additional 55 N-Terminal AA's Not Present in
SHBs; All HBs Are Involved in Envelope Formation and the Formation of SVPs
Found in the Serum
SHBs is the HBV's Small Surface Protein and it is Encoded By the Transcripts from
the S Promoter; It is the Smallest and Most Abundant Surface Protein, and it Binds
to the HSBGs Present on Host Cell Surfaces; All HBs Are Involved in Envelope
Formation and the Formation of SVPs Found in the Serum
The Core Proteins HBc is the Major Component of the Viral Nucleocapsid, Which
Packages the the Viral Genome into the Mature Virion, and it Readily Dimerizes
to Produce the Icosahedral Structure of the Nucleocapsid (T = 4); HBe is
Translocated to the ER After Translation and its True Function is Still Unknown (It
May Suppress the Host Immune System at High Levels and Prevent it From
Eliminating Cells Containing HBV)
HBx is the Virus' Regulatory Protein and it is Translated From the Shortest of the 5
Viral mRNAs; HBx is Not Found in Mature Virions or Nucleocapsids But it
Stimulates Early Viral Gene Transcription; HBx Also Up-Regulates Multiple
Proteins and Interacts With the Tumor Suppressor Protein p53
Host Immune Response Factor that Results in Hypoacetylation of cccDNA,
Converting it into a Closed, Inactive Form, and Repressing Transcription
Virus Release: Budding Detachment of the Virion inside of MVB/MVB-Derived
Exosome Through Membrane Scission; Recruits VPS4 ATPases
to Complete Membrane Fission
Virus Release: ALIX is a Regulator of Capsid Budding that Also Mediates an ESCRTIndependent Pathway of HBV Egress Involving Naked Capsids
DR1 is a 12 NT Direct Repeat Sequence On rcDNA of HBV that Serves as the Site of
Translocation During 1st Strand Transfer of (-) Strand DNA Synthesis During
Reverse Transcription; DR2 is a 12 NT Direct Repeat Sequence on the (-) Strand
DNA and Serves as the Primer Site for Initiating (+) Strand DNA Synthesis; DR2
Sequences at Both 5' Ends Also Form the Hydrogen Bonding Between the 2 DNA
Strands in the rcDNA Genome
Origin
Host
Host
Host
Host
Host
Host
Host
Host
Virus
Host
Virus
Host
Host
Virus
Virus
Virus
Virus
Virus
Virus
Virus
Virus
Virus
Host
Host
Host
Virus