hNTCP‑expressing primary pig hepatocytes are a valuable tool for investigating hepatitis B virus infection and antiviral drugs.

Primary human hepatocytes (PHHs) are the 'gold standard' for investigating hepatitis B virus (HBV) infection and antiviral drugs. However, poor availability, variation between batches and ethical issues regarding PHHs limit their applications. The discovery of human sodium taurocholate co‑transporting polypeptide (hNTCP) as a functional HBV receptor has enabled the development of a surrogate model to supplement the use of PHHs.

Hepatitis B virus infection: Defective surface antigen expression and pathogenesis.

Hepatitis B virus (HBV) infection is a global public health concern. HBV causes chronic infection in patients and can lead to liver cirrhosis, hepatocellular carcinoma, and other severe liver diseases. Thus, understanding HBV-related pathogenesis is of particular importance for prevention and clinical intervention.

Genetic variation of hepatitis B virus and its significance for pathogenesis.

Hepatitis B virus (HBV) has a worldwide distribution and is endemic in many populations. Due to its unique life cycle which requires an error-prone reverse transcriptase for replication, it constantly evolves, resulting in tremendous genetic variation in the form of genotypes, sub-genotypes, and mutations. In recent years, there has been considerable research on the relationship between HBV genetic variation and HBV-related pathogenesis, which has profound implications in the natural history of HBV infection, viral detection, immune prevention, drug treatment and prognosis.

The protamine-like DNA-binding protein P6.9 epigenetically up-regulates Autographa californica multiple nucleopolyhedrovirus gene transcription in the late infection phase.

Protamines are a group of highly basic proteins first discovered in spermatozoon that allow for denser packaging of DNA than histones and will result in down-regulation of gene transcription[1]. It is well recognized that the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) encodes P6.9, a protamine-like protein that forms the viral subnucleosome through binding to the viral genome[29].

Putative phosphorylation sites on WCA domain of HA2 is essential for Helicoverpa armigera single nucleopolyhedrovirus replication.

Protein phosphorylation is one of the most common post-translational modification processes that play an essential role in regulating protein functionality. The Helicoverpa armigera single nucleopolyhedrovirus (HearNPV) orf2-encoded nucleocapsid protein HA2 participates in orchestration of virus-induced actin polymerization through its WCA domain, in which phosphorylation status are supposed to be critical in respect to actin polymerization. In the present study, two putative phosphorylation sites ((232)Thr and (250)Ser) and a highly conserved Serine ((245)Ser) on the WCA domain of HA2 were mutated, and their phenotypes were characterized by reintroducing the mutated HA2 into the HearNPV genome.

Novel evidence suggests Hepatitis B virus surface proteins participate in regulation of HBV genome replication.

Naturally occurring mutations in surface proteins of Hepatitis B virus (HBV) usually result in altered hepatitis B surface antigen (HBsAg) secretion efficiency. In the present study, we reported two conserved residues, M75 and M103 with respect to HBsAg, mutations of which not only attenuated HBsAg secretion (M75 only), but also suppressed HBV genome replication without compromising the overlapping p-gene product. We also found M75 and M103 can initiate truncated surface protein (TSPs) synthesis upon over-expression of full-length surface proteins, which may possibly contribute to HBV genome replication.