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Pley C, Lourenço J, McNaughton AL, Matthews PC. Spacer Domain in Hepatitis B Virus Polymerase: Plugging a Hole or Performing a Role? J Virol 2022; 96:e0005122. [PMID: 35412348 PMCID: PMC9093120 DOI: 10.1128/jvi.00051-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
Hepatitis B virus (HBV) polymerase is divided into terminal protein, spacer, reverse transcriptase, and RNase domains. Spacer has previously been considered dispensable, merely acting as a tether between other domains or providing plasticity to accommodate deletions and mutations. We explore evidence for the role of spacer sequence, structure, and function in HBV evolution and lineage, consider its associations with escape from drugs, vaccines, and immune responses, and review its potential impacts on disease outcomes.
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Affiliation(s)
- Caitlin Pley
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - José Lourenço
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
| | - Anna L. McNaughton
- Population Health Science, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
| | - Philippa C. Matthews
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Division of Infection and Immunity, University College London, London, United Kingdom
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Hao R, Xiang K, Shi Y, Zhao D, Tian H, Xu B, Zhu Y, Dong H, Ding H, Zhuang H, Hu J, Li T. Naturally Occurring Mutations within HBV Surface Promoter II Sequences Affect Transcription Activity, HBsAg and HBV DNA Levels in HBeAg-Positive Chronic Hepatitis B Patients. Viruses 2019; 11:v11010078. [PMID: 30669266 PMCID: PMC6356792 DOI: 10.3390/v11010078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/13/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Mutations in hepatitis B virus (HBV) surface promoter II (SPII) have not been well studied in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients. We aimed to investigate SPII mutations in such patients and their biological and clinical impacts. Direct sequencing was used to detect SPII mutations in 106 HBeAg-positive treatment-naïve CHB patients with genotype C (82.1% (87/106) was C2) HBV infection. Results showed that mutation frequency in transcription factor (TF) unbinding region was significantly higher than that in TF binding region of SPII (C1: 3.4% vs. 1.3%; C2: 2.6% vs. 1.3%; p < 0.0001). Luciferase assay revealed distinct promoter activities among SPII mutants; especially SPII of G120A mutant had a 15-fold higher activity than that of wild-type (p < 0.001). In vitro experiments in HepG2 cells showed that G82A, A115C and G120A mutants increased the hepatitis B surface antigen (HBsAg) levels, while C18T had an opposite effect. G82A, A115C and G120A mutants boosted the intracellular HBV total RNA level. G120A mutation resulted in an increased HBV DNA level in vitro, consistent with the serological results in patients. Thus, novel SPII mutations would affect promoter activity, HBsAg, HBV DNA and HBV total RNA levels, suggesting their potential biological and clinical significances.
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Affiliation(s)
- Ran Hao
- School of Nursing, Hebei Medical University, Shijiazhuang 050000, Hebei, China.
| | - Kuanhui Xiang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
| | - Yan Shi
- Institute of Microbiology, Shijiazhuang Center for Disease Control and Prevention, Shijiazhuang 050000, Hebei, China.
| | - Dong Zhao
- Institute of Microbiology, Shijiazhuang Center for Disease Control and Prevention, Shijiazhuang 050000, Hebei, China.
| | - Huifang Tian
- Institute of Microbiology, Shijiazhuang Center for Disease Control and Prevention, Shijiazhuang 050000, Hebei, China.
| | - Baohong Xu
- Institute of Microbiology, Shijiazhuang Center for Disease Control and Prevention, Shijiazhuang 050000, Hebei, China.
| | - Yufang Zhu
- School of Nursing, Hebei Medical University, Shijiazhuang 050000, Hebei, China.
| | - Huan Dong
- School of Nursing, Hebei Medical University, Shijiazhuang 050000, Hebei, China.
| | - Hai Ding
- Hunan Sansure Biotech Incorporation, Lusong Road, Changsha 410000, Hunan, China.
| | - Hui Zhuang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
| | - Jie Hu
- School of Nursing, Hebei Medical University, Shijiazhuang 050000, Hebei, China.
| | - Tong Li
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
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Lupberger J, Schaedler S, Peiran A, Hildt E. Identification and characterization of a novel bipartite nuclear localization signal in the hepatitis B virus polymerase. World J Gastroenterol 2013; 19:8000-8010. [PMID: 24307793 PMCID: PMC3848147 DOI: 10.3748/wjg.v19.i44.8000] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/10/2013] [Accepted: 09/17/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To characterize the nuclear import of hepatitis B virus (HBV) polymerase (P) and its relevance for the viral life cycle.
METHODS: Sequence analysis was performed to predict functional motives within P. Phosphorylation of P was analyzed by in vitro phosphorylation. Phosphorylation site and nuclear localization signal (NLS) were destroyed by site directed mutagenesis. Functionality of the identified NLS was analyzed by confocal fluorescence microscopy and characterizing the karyopherin binding. Relevance of the structural motives for viral life cycle was studied by infection of primary Tupaia hepatocytes with HBV.
RESULTS: We identified by sequence alignment and functional experiments a conserved bipartite NLS containing a casein kinase II (CKII) phosphorylation site located within the terminal protein domain (TP) of the HBV polymerase. Inhibition of CKII impairs the functionality of this NLS and thereby prevents the nuclear import of the polymerase. Binding of the import factor karyopherin-α2 to the polymerase depends on its CKII-mediated phosphorylation of the bipartite NLS. In HBV-infected primary Tupaia hepatocytes CKII inhibition in the early phase (post entry phase) of the infection process prevents the establishment of the infection.
CONCLUSION: Based on these data it is suggested that during HBV infection the final import of the genome complex into the nucleus is mediated by a novel bipartite NLS localized in the TP domain of HBV polymerase.
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Chang H, Lo SJ. Modification with a phosphorylation tag of PKA in the TraT-based display vector of Escherichia coli. J Biotechnol 2000; 78:115-22. [PMID: 10725535 DOI: 10.1016/s0168-1656(99)00227-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have previously developed the TraT display system to express the preS1 peptide of human hepatitis B virus (HBV) and the snake venom rhodostomin (RHO) on the surface of Escherichia coli. In this study, we modified the pT2 vector by adding a thrombin cutting site and a phosphorylation tag of protein kinase A before the multiple restriction enzyme sites. The modified vector allowed us to label the TraT fusion protein (TraT-RHO) with [32P] and to increase the detection sensitivity of TraT-RHO expression bacteria binding to and being internalized into BHK-21 cells. After the thrombin cleavage, the isotope labeled RHO could be detected in a free form. We therefore suggest that the new version of pT2 vector, pT2-KL, will facilitate to identify the counterpart of displayed peptide.
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Affiliation(s)
- H Chang
- Institute of Microbiology, School of Life Science, National Yang-Ming University, Taipei, Taiwan ROC
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Chen HK, Pai CY, Huang JY, Yeh NH. Human Nopp140, which interacts with RNA polymerase I: implications for rRNA gene transcription and nucleolar structural organization. Mol Cell Biol 1999; 19:8536-46. [PMID: 10567578 PMCID: PMC84972 DOI: 10.1128/mcb.19.12.8536] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nopp140 is thought to shuttle between nucleolus and cytoplasm. However, the predominant nucleolar localization of Nopp140 homologues from different species suggests that Nopp140 is also involved in events occurring within the nucleolus. In this study, we demonstrated that the largest subunit of RNA polymerase I, RPA194, was coimmunoprecipitated with the human Nopp140 (hNopp140). Such an interaction is mediated through amino acids 204 to 382 of hNopp140. By double immunofluorescence, hNopp140 was colocalized with RNA polymerase I at the rDNA (rRNA genes) transcription active foci in the nucleolus. These results suggest that Nopp140 can interact with RNA polymerase I in vivo. Transfected cells expressing the amino-terminal half of hNopp140, hNopp140N382 (amino acids 1 to 382), displayed altered nucleoli with crescent-shaped structures. This phenotype is reminiscent of the segregated nucleoli induced by actinomycin D treatment, which is known to inhibit rRNA synthesis. Consistently, the hNopp140N382 protein mislocalized the endogenous RNA polymerase I and shut off cellular rRNA gene transcription as revealed by an in situ run-on assay. These dominant negative effects of the mutant hNopp140N382 suggest that Nopp140 plays an essential role in rDNA transcription. Interestingly, ectopic expression of hNopp140 to a very high level caused the formation of a transcriptionally inactive spherical structure occupying the entire nucleolar area which trapped the RNA polymerase I, fibrillarin, and hNopp140 but excluded the nucleolin. The mislocalizations of these nucleolar proteins after hNopp140 overexpression imply that Nopp140 may also play roles in maintenance of nucleolar integrity.
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Affiliation(s)
- H K Chen
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 11221, Republic of China
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Hui EKW, Chen KL, Lo SJ. Hepatitis B virus maturation is affected by the incorporation of core proteins having a C-terminal substitution of arginine or lysine stretches. J Gen Virol 1999; 80 ( Pt 10):2661-2671. [PMID: 10573159 DOI: 10.1099/0022-1317-80-10-2661] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Assembly of replication-competent hepadnavirus nucleocapsids requires interaction of core protein, polymerase and encapsidation signal (epsilon) with viral pregenomic RNA. The N-terminal portion (aa 1-149) of the core protein is able to self-assemble into nucleocapsids, whereas the C-terminal portion (aa 150-183) is known to interact with pregenomic RNA. In this study, two hepatitis B virus (HBV) core mutants (C144Arg and C144Lys) in which the C-terminal SPRRR (Ser-Pro-Arg-Arg-Arg) motif was replaced by a stretch of arginine or lysine residues were generated to test their role in pregenome encapsidation and virus maturation. Mutant or wild-type core-expression plasmids were co-transfected with a core-negative plasmid into human hepatoma HuH-7 cells to compare trans-complementation efficiency for virus replication. Both low- and high-density capsids were present in -the cytoplasm and culture medium of HuH-7 cells in all transfections. Nucleocapsids formed by C144Arg and C144Lys, however, lost the endogenous polymerase activity to repair HBV DNA. Furthermore, in co-transfection of pHBVC144Arg or pHBVC144Lys with a plasmid which produces replication-competent nucleocapsids, the HBV DNA repairing signal was reduced 40- to 80-fold. This is probably due to formation of mosaic particles of wild-type and mutant cores. Results indicated that the SPRRR motif at the core protein C terminus is important for HBV DNA replication and maturation. Additionally, triple-plasmid transfection experiments showed that nucleocapsids containing various amounts of C144Arg and wild-type core proteins exhibited a bias in selecting a shorter pregenome for encapsidation and DNA replication. It is therefore suggested that unknown factors are also involved in HBV pregenome packaging.
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Affiliation(s)
- Eric Ka-Wai Hui
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
| | - Kun-Lin Chen
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
| | - Szecheng J Lo
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
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