N‐Terminal PreS1 Sequence Regulates Efficient Infection of Cell‐Culture–Generated Hepatitis B Virus

Abstract

Background and Aims An efficient cell‐culture system for hepatitis B virus (HBV) is indispensable for research on viral characteristics and antiviral reagents. Currently, for the HBV infection assay in cell culture, viruses derived from HBV genome‐integrated cell lines of HepG2.2.15 or HepAD‐38 are commonly used. However, these viruses are not suitable for the evaluation of polymorphism‐dependent viral characteristics or resistant mutations against antiviral reagents. HBV obtained by the transient transfection of the ordinary HBV molecular clone has limited infection efficiencies in cell culture. Approach and Results We found that an 11‐amino‐acid deletion (d11) in the preS1 region enhances the infectivity of cell‐culture–generated HBV (HBVcc) to sodium taurocholate cotransporting polypeptide–transduced HepG2 (HepG2/NTCP) cells. Infection of HBVcc derived from a d11‐introduced genotype C strain (GTC‐d11) was ~10‐fold more efficient than infection of wild‐type GTC (GTC‐wt), and the number of infected cells was comparable between GTC‐d11‐ and HepG2.2.15‐derived viruses when inoculated with the same genome equivalents. A time‐dependent increase in pregenomic RNA and efficient synthesis of covalently closed circular DNA were detected after infection with the GTC‐d11 virus. The involvement of d11 in the HBV large surface protein in the enhanced infectivity was confirmed by an HBV reporter virus and hepatitis D virus infection system. The binding step of the GTC‐d11 virus onto the cell surface was responsible for this efficient infection. Conclusions This system provides a powerful tool for studying the infection and propagation of HBV in cell culture and also for developing the antiviral strategy against HBV infection.

The Regulation of circRNA RNF13/miRNA-1224-5p Axis Promotes the Malignant Evolution in Acute Myeloid Leukemia

“…Circular RNAs are a kind of single-strand noncoding RNAs that widely exist in organisms [ 9 ]. They were first found in plant viruses in 1970s and then successively found in hepatitis D virus and yeast mitochondria [ 10 ]. In the early studies, circRNA was thought to be formed from the wrong splicing of exon transcripts.…”

Hepatitis B Virus Entry into Cells

“…The region between amino acids 2 and 47 in preS1 has been implicated in binding to hepatocytes [ 61 , 62 , 63 ]. Recently, it has been observed that the sequence of the preS1 could modulate infectivity [ 64 ]. Indeed, it has been found that an 11 amino acid deletion in the preS1 region enhances the infectivity of HBV particles.…”

Novel Genetic Rearrangements in Hepatitis B Virus: Complex Structural Variations and Structural Variation Polymorphisms

“…Previous experimental data have shown that removing an insertional SV of 36 nt length in HBV/G caused a reduction in both the core protein expression and suppression of genome replication [ 70 ]. In addition, a recent study by Murayama and colleagues [ 71 ] showed that removing a 33 nt SV polymorphism in HBV/C, which changed the HBV/C construct in part of the pre-S1 region into SV polymorphisms in HBV/D and primate HBVs, caused a 10-times higher replication of the viral genome as compared with a wild-type HBV/C construct. Similar data were reported by Tong and colleagues [ 72 ].…”