Stimulation of RNA Polymerase II Elongation by Hepatitis Delta Antigen

Science ◽  
2001 ◽  
Vol 293 (5527) ◽  
pp. 124-127 ◽  
Author(s):  
Y. Yamaguchi
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Hepatitis Delta ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen ◽  
Stimulation Of

scholarly journals Phosphorylation of Serine 177 of the Small Hepatitis Delta Antigen Regulates Viral Antigenomic RNA Replication by Interacting with the Processive RNA Polymerase II

2009 ◽  
Vol 84 (3) ◽  
pp. 1430-1438 ◽  
Author(s):  
Shiao-Ya Hong ◽  
Pei-Jer Chen
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Posttranslational Modifications ◽  
Transcription Initiation ◽  
Kinase Inhibitor ◽  
Rna Replication ◽  
Hepatitis Delta ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen ◽  
Rnap Ii

ABSTRACT Recent studies revealed that posttranslational modifications (e.g., phosphorylation and methylation) of the small hepatitis delta antigen (SHDAg) are required for hepatitis delta virus (HDV) replication from antigenomic to genomic RNA. The phosphorylation of SHDAg at serine 177 (Ser177) is involved in this step, and this residue is crucial for interaction with RNA polymerase II (RNAP II), the enzyme assumed to be responsible for antigenomic RNA replication. This study demonstrated that SHDAg dephosphorylated at Ser177 interacted preferentially with hypophosphorylated RNAP II (RNAP IIA), which generally binds at the transcription initiation sites. In contrast, the Ser177-phosphorylated counterpart (pSer177-SHDAg) exhibited preferential binding to hyperphosphorylated RNAP II (RNAP IIO). In addition, RNAP IIO associated with pSer177-SHDAg was hyperphosphorylated at both the Ser2 and Ser5 residues of its carboxyl-terminal domain (CTD), which is a hallmark of the transcription elongation isoform. Moreover, the RNAP II CTD kinase inhibitor 5,6-dichloro-1-β-d-ribofuranosyl-benzimidazole (DRB) not only blocked the interaction between pSer177-SHDAg and RNAP IIO but also inhibited HDV antigenomic replication. Our results suggest that the phosphorylation of SHDAg at Ser177 shifted its affinity toward the RNA RNAP IIO isoform and thus is a switch for HDV antigenomic RNA replication from the initiation to the elongation stage.

Hepatitis delta antigen binds to the clamp of RNA polymerase II and affects transcriptional fidelity

2007 ◽  
Vol 12 (7) ◽  
pp. 863-875 ◽  
Author(s):  
Yuki Yamaguchi ◽  
Takashi Mura ◽  
Sittinan Chanarat ◽  
Sachiko Okamoto ◽  
Hiroshi Handa
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Hepatitis Delta ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen

scholarly journals Nucleolar Targeting of Hepatitis Delta Antigen Abolishes Its Ability To Initiate Viral Antigenomic RNA Replication

2007 ◽  
Vol 82 (2) ◽  
pp. 692-699 ◽  
Author(s):  
Wen-Hung Huang ◽  
Yen-Shun Chen ◽  
Pei-Jer Chen
Keyword(s):  
Subcellular Localization ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Synthesis ◽  
Rna Virus ◽  
Rna Replication ◽  
Genomic Rna ◽  
Hepatitis Delta ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen

ABSTRACT Hepatitis delta virus (HDV) is a small RNA virus that contains one 1.7-kb single-stranded circular RNA of negative polarity. The HDV particle also contains two isoforms of hepatitis delta antigen (HDAg), small (SHDAg) and large HDAg. SHDAg is required for the replication of HDV, which is presumably carried out by host RNA-dependent RNA polymerases. The localization and the HDAg and host RNA polymerase responsible for HDV replication remain important issues to be addressed. In this study, using recombinant SHDAg fused with a heterologous nucleolar localization sequence (NoLS) to confine its subcellular localization in nucleoli, we aimed to study the effect of SHDAg subcellular localization on HDV RNA replication. The initiation of genomic RNA synthesis from antigenomic template was hardly detectable when SHDAg was fused with the NoLS motif and localized mainly in nucleoli. In contrast, the initiation of antigenomic RNA synthesis was not affected. Drug treatment to release a SHDAg-NoLS mutant from nucleoli could partially restore the replication of HDV genomic RNA from antigenomic RNA. This also recovered the cointeraction between SHDAg and RNA polymerase II. These data strongly suggest that nuclear polymerase (RNA polymerase II) is involved in the synthesis of genomic RNA and that the synthesis of antigenomic RNA can occur in nucleoli. Our results support the idea that the replication of HDV genomic RNA or antigenomic RNA is likely to be carried out by different machineries in different subcellular localizations.

scholarly journals Transcription of Hepatitis Delta Virus RNA by RNA Polymerase II

2007 ◽  
Vol 82 (3) ◽  
pp. 1118-1127 ◽  
Author(s):  
Jinhong Chang ◽  
Xingcao Nie ◽  
Ho Eun Chang ◽  
Ziying Han ◽  
John Taylor
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Hepatitis Delta Virus ◽  
Cell System ◽  
Hepatitis Delta ◽  
Pol Ii ◽  
Delta Antigen ◽  
Nuclear Extracts ◽  
Virus Rna ◽  
Delta Virus

ABSTRACT Previous studies have indicated that the replication of the RNA genome of hepatitis delta virus (HDV) involves redirection of RNA polymerase II (Pol II), a host enzyme that normally uses DNA as a template. However, there has been some controversy about whether in one part of this HDV RNA transcription, a polymerase other than Pol II is involved. The present study applied a recently described cell system (293-HDV) of tetracycline-inducible HDV RNA replication to provide new data regarding the involvement of host polymerases in HDV transcription. The data generated with a nuclear run-on assay demonstrated that synthesis not only of genomic RNA but also of its complement, the antigenome, could be inhibited by low concentrations of amanitin specific for Pol II transcription. Subsequent studies used immunoprecipitation and rate-zonal sedimentation of nuclear extracts together with double immunostaining of 293-HDV cells, in order to examine the associations between Pol II and HDV RNAs, as well as the small delta antigen, an HDV-encoded protein known to be essential for replication. Findings include evidence that HDV replication is somehow able to direct the available delta antigen to sites in the nucleoplasm, almost exclusively colocalized with Pol II in what others have described as transcription factories.

scholarly journals Large Isoform of Hepatitis Delta Antigen Activates Serum Response Factor-associated Transcription

2000 ◽  
Vol 275 (48) ◽  
pp. 37311-37316 ◽  
Author(s):  
Tadashi Goto ◽  
Naoya Kato ◽  
Suzane Kioko Ono-Nita ◽  
Hideo Yoshida ◽  
Motoyuki Otsuka ◽  
...  
Keyword(s):  
Serum Response Factor ◽  
Response Factor ◽  
Hepatitis Delta ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen ◽  
Serum Response

scholarly journals Multimerization of Hepatitis Delta Antigen Is a Critical Determinant of RNA Binding Specificity

2009 ◽  
Vol 84 (3) ◽  
pp. 1406-1413 ◽  
Author(s):  
Brian C. Lin ◽  
Dawn A. Defenbaugh ◽  
John L. Casey
Keyword(s):  
Conformational Changes ◽  
Rna Binding ◽  
Site Directed Mutagenesis ◽  
Minimum Length ◽  
Critical Determinant ◽  
Hepatitis Delta ◽  
Ribonucleoprotein Complex ◽  
Delta Antigen ◽  
Hepatitis Delta Antigen

ABSTRACT Hepatitis delta virus (HDV) RNA forms an unbranched rod structure that is associated with hepatitis delta antigen (HDAg) in cells replicating HDV. Previous in vitro binding experiments using bacterially expressed HDAg showed that the formation of a minimal ribonucleoprotein complex requires an HDV unbranched rod RNA of at least about 300 nucleotides (nt) and suggested that HDAg binds the RNA as a multimer of fixed size. The present study specifically examines the role of HDAg multimerization in the formation of the HDV ribonucleoprotein complex (RNP). Disruption of HDAg multimerization by site-directed mutagenesis was found to profoundly alter the nature of RNP formation. Mutant HDAg proteins defective for multimerization exhibited neither the 300-nt RNA size requirement for binding nor specificity for the unbranched rod structure. The results unambiguously demonstrate that HDAg binds HDV RNA as a multimer and that the HDAg multimer is formed prior to binding the RNA. RNP formation was found to be temperature dependent, which is consistent with conformational changes occurring on binding. Finally, analysis of RNPs constructed with unbranched rod RNAs successively longer than the minimum length indicated that multimeric binding is not limited to the first HDAg bound and that a minimum RNA length of between 604 and 714 nt is required for binding of a second multimer. The results confirm the previous proposal that HDAg binds as a large multimer and demonstrate that the multimer is a critical determinant of the structure of the HDV RNP.

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