RNA Editing in Hepatitis Delta Virus

Casey, John

doi:10.1007/3-540-29802-9_4

Cited by 55 publications

(62 citation statements)

References 75 publications

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“…Overexpression approaches failed to demonstrate an antiviral activity of either ADAR1 or ADAR2 in single-cycle infections with vesicular stomatitis virus (Li and others 2010). While ADAR1 antiviral activity is implicated in some studies with 2 hepatitis viruses, HCV (Taylor and others Under normal physiologic conditions, ADAR1 promotes rather than inhibits HDV replication (Casey 2006). HDV has a structured, circular RNA genome and depends on a helper virus, hepatitis B virus, for replication.…”

Section: Virus Growth and Persistencementioning

confidence: 99%

“…Without editing, genome packaging does not occur; ADAR1, therefore, is necessary for virus replication. However, high levels of ADAR1 protein inhibit HDV replication ( Jayan and Casey 2002a;Hartwig and others 2004;Casey 2006). Overexpression of ADAR1 or ADAR2 in Huh-7 cells, or treatment with IFN that induces the p150 form of ADAR1, results in increased HDV RNA editing and decreased HDV replication ( Jayan and Casey 2002a;Hartwig and others 2004).…”

Section: Virus Growth and Persistencementioning

confidence: 99%

“…Overexpression of ADAR1 or ADAR2 in Huh-7 cells, or treatment with IFN that induces the p150 form of ADAR1, results in increased HDV RNA editing and decreased HDV replication ( Jayan and Casey 2002a;Hartwig and others 2004). Likewise, a replication-competent HDV virus mutant that shows increased editing at the amber/W site produces increased amounts of large HDAg early in infection, and replication of the mutant virus terminates prematurely (Sato and others 2004;Casey 2006). It is not unreasonable to presume that an antiviral activity for ADAR1 against HDV might occur during natural infection, especially if the level of ADAR1 p150 is increased during IFN-a therapy for hepatitis B virus (HBV).…”

Section: Virus Growth and Persistencementioning

confidence: 99%

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Adenosine Deaminases Acting on RNA, RNA Editing, and Interferon Action

George

Gan

Liu

et al. 2011

Journal of Interferon & Cytokine Research

107

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Adenosine deaminases acting on RNA (ADARs) catalyze adenosine (A) to inosine (I) editing of RNA that possesses double-stranded (ds) structure. A-to-I RNA editing results in nucleotide substitution, because I is recognized as G instead of A both by ribosomes and by RNA polymerases. A-to-I substitution can also cause dsRNA destabilization, as I:U mismatch base pairs are less stable than A:U base pairs. Three mammalian ADAR genes are known, of which two encode active deaminases (ADAR1 and ADAR2). Alternative promoters together with alternative splicing give rise to two protein size forms of ADAR1: an interferon-inducible ADAR1-p150 deaminase that binds dsRNA and Z-DNA, and a constitutively expressed ADAR1-p110 deaminase. ADAR2, like ADAR1-p110, is constitutively expressed and binds dsRNA. A-to-I editing occurs with both viral and cellular RNAs, and affects a broad range of biological processes. These include virus growth and persistence, apoptosis and embryogenesis, neurotransmitter receptor and ion channel function, pancreatic cell function, and posttranscriptional gene regulation by microRNAs. Biochemical processes that provide a framework for understanding the physiologic changes following ADAR-catalyzed A-to-I ( ¼ G) editing events include mRNA translation by changing codons and hence the amino acid sequence of proteins; pre-mRNA splicing by altering splice site recognition sequences; RNA stability by changing sequences involved in nuclease recognition; genetic stability in the case of RNA virus genomes by changing sequences during viral RNA replication; and RNAstructure-dependent activities such as microRNA production or targeting or protein-RNA interactions.

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Section: Virus Growth and Persistencementioning

confidence: 99%

Section: Virus Growth and Persistencementioning

confidence: 99%

Section: Virus Growth and Persistencementioning

confidence: 99%

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Adenosine Deaminases Acting on RNA, RNA Editing, and Interferon Action

George

Gan

Liu

et al. 2011

Journal of Interferon & Cytokine Research

107

View full text Add to dashboard Cite

show abstract

“…This structure is short, with a predicted free energy of -35 kcal/mole (mfold at 37°C; Mathews et al 1999;Zuker 2003). Although selective editing usually occurs in structures that are less stable than those promoting nonselective editing, this is not always the case, as exemplified by editing of the antigenomic RNA of hepatitis delta virus (HDV; for review, see Casey 2006). The ~1700-nucleotide HDV RNA folds into a "rod-like" helical structure with a predicted free energy of -930 kcal/mol (mfold at 37°C).…”

Section: Adar Basicsmentioning

confidence: 99%

How Does RNA Editing Affect dsRNA-mediated Gene Silencing?

Bass¹

2006

Cold Spring Harbor Symposia on Quantitative Biology

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In general, double-stranded RNA (dsRNA)-binding proteins (dsRBPs) are not sequence-specific. A dsRNA molecule in a cell will interact with any dsRBP it comes in contact with, suggesting that different dsRNA-mediated pathways intersect and affect each other. This paper analyzes evidence that the ADAR RNA editing enzymes, which act on dsRNA, affect dsRNA-mediated gene silencing pathways. Examples of how ADARs alter gene silencing pathways such as RNA interference, as well as mechanisms that allow the pathways to coexist and maintain their unique functions, are discussed.

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“…Among the RNA transcripts edited selectively by ADARs at one or a few sites that affect translational decoding, the best characterized include cellular RNAs that encode neurotransmitter receptors for L-glutamine (GluR-B) and serotonin (5HT-2cR) (4,15,24,27,42) and hepatitis delta virus (HDV) antigenome viral RNA (5,45). In these cases, A-to-I RNA editing is highly site specific and leads to the synthesis of new protein products with altered functions.…”

mentioning

confidence: 99%

Host Response to Polyomavirus Infection Is Modulated by RNA Adenosine Deaminase ADAR1 but Not by ADAR2

George

Samuel

2011

J Virol

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Adenosine deaminases acting on RNA (ADARs) catalyze the C-6 deamination of adenosine (A) to produce inosine (I), which behaves as guanine (G), thereby altering base pairing in RNAs with double-stranded character. Two genes, adar1 and adar2, are known to encode enzymatically active ADARs in mammalian cells. Furthermore, two size forms of ADAR1 are expressed by alternative promoter usage, a short (p110) nuclear form that is constitutively made and a long (p150) form that is interferon inducible and present in both the cytoplasm and nucleus. ADAR2 is also a constitutively expressed nuclear protein. Extensive A-to-G substitution has been described in mouse polyomavirus (PyV) RNA isolated late times after infection, suggesting modification by ADAR. To test the role of ADAR in PyV infection, we used genetically null mouse embryo fibroblast cells deficient in either ADAR1 or ADAR2. The single-cycle yields and growth kinetics of PyV were comparable between adar1 ؊/؊ and adar2 ؊/؊ genetic null fibroblast cells. While large T antigen was expressed to higher levels in adar1 ؊/؊ cells than adar2 ؊/؊ cells, less difference was seen in VP1 protein expression levels between the two knockout MEFs. However, virus-induced cell killing was greatly enhanced in PyV-infected adar1 ؊/؊ cells compared to that of adar2 ؊/؊ cells. Complementation with p110 protected cells from PyVinduced cytotoxicity. UV-irradiated PyV did not display any enhanced cytopathic effect in adar1 ؊/؊ cells. Reovirus and vesicular stomatitis virus single-cycle yields were comparable between adar1 ؊/؊ and adar2 ؊/؊ cells, and neither reovirus nor VSV showed enhanced cytotoxicity in adar1 ؊/؊ -infected cells. These results suggest that ADAR1 plays a virus-selective role in the host response to infection.

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RNA Editing in Hepatitis Delta Virus

Cited by 55 publications

References 75 publications

Adenosine Deaminases Acting on RNA, RNA Editing, and Interferon Action

Adenosine Deaminases Acting on RNA, RNA Editing, and Interferon Action

How Does RNA Editing Affect dsRNA-mediated Gene Silencing?

Host Response to Polyomavirus Infection Is Modulated by RNA Adenosine Deaminase ADAR1 but Not by ADAR2

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