Hepadnaviral Protein Expression Vectors
Hepadnavirus includes Hepatitis B virus. Hepatitis B viral protein expression vectors are derived from NCBI reference sequence NC_003977.2. All of the expression vectors are codon optimized for mammalian cell expression. Choose to add a GFP or his tag to the C terminal end of any protein. A CMV promoter is used for mammalian cell expression and the backbone contains a selection marker for Geneticin (G418). All non-tagged glycoprotein expression vectors have been functionally validated using pseudotyped viral particles.
Hepadnavirus, specifically Hepatitis B (HBV), is an enveloped partially double-stranded DNA virus that belongs to the Hepadnaviridae family. HBV is commonly transmitted from mother to child during birth or delivery and through contact with blood or body fluids of an infected person. HBV attacks the liver (hepatocytes) which can lead to cirrhosis, hepatocellular carcinoma (liver cancer), and eventually death. The burden of HBV infection is highest in Africa and Asia, which made up of 800,000 deaths in 2019. HBV genome encodes a polymerase surrounded by a nucleocapsid and three envelope proteins called the large (L), middle (M), and small (S) surface proteins. The C-terminal S domain is common to all three envelope proteins. The M protein contains an extra N-terminal preS2 domain, and the L protein contains a preS1 domain in addition to the preS2 and S domains. The envelope proteins contain domains essential for attachment to hepatocytes. HBV enters the host cell (hepatocyte) by binding to heparan sulfate proteoglycans (HSPGs) on the host’s cell membrane using the sodium taurocholate co-transporting polypeptide (NTCP) receptor and epidermal growth factor receptor (EGFR) coreceptor. This internalization complex is associated with E-cadherin linked to N-glycosylated NTCP, allowing the relocalization of NTCP to the plasma membrane. The HBV–NTCP–EGFR complex is then taken up into the cell by clathrin-mediated endocytosis. The EGFR’s sorting machinery coordinates HBV transport in the endosomal network, triggering endosomal fusion and releasing viral genome into the cytoplasm.