scholarly journals 3,7-Dihydroxytropolones Inhibit Initiation of Hepatitis B Virus Minus-Strand DNA Synthesis

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4434
Author(s):  
Ellen Bak ◽  
Jennifer T. Miller ◽  
Andrea Noronha ◽  
John Tavis ◽  
Emilio Gallicchio ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Reverse Transcriptase ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Rnase H ◽  
Initiation Complex ◽  
Cis Acting ◽  
B Virus

Initiation of protein-primed (-) strand DNA synthesis in hepatitis B virus (HBV) requires interaction of the viral reverse transcriptase with epsilon (ε), a cis-acting regulatory signal located at the 5’ terminus of pre-genomic RNA (pgRNA), and several host-encoded chaperone proteins. Binding of the viral polymerase (P protein) to ε is necessary for pgRNA encapsidation and synthesis of a short primer covalently attached to its terminal domain. Although we identified small molecules that recognize HBV ε RNA, these failed to inhibit protein-primed DNA synthesis. However, since initiation of HBV (-) strand DNA synthesis occurs within a complex of viral and host components (e.g., Hsp90, DDX3 and APOBEC3G), we considered an alternative therapeutic strategy of allosteric inhibition by disrupting the initiation complex or modifying its topology. To this end, we show here that 3,7-dihydroxytropolones (3,7-dHTs) can inhibit HBV protein-primed DNA synthesis. Since DNA polymerase activity of a ribonuclease (RNase H)-deficient HBV reverse transcriptase that otherwise retains DNA polymerase function is also abrogated, this eliminates direct involvement of RNase (ribonuclease) H activity of HBV reverse transcriptase and supports the notion that the HBV initiation complex might be therapeutically targeted. Modeling studies also provide a rationale for preferential activity of 3,7-dHTs over structurally related α-hydroxytropolones (α-HTs).

Inhibitory Effects of Acyclic Nucleoside Phosphonate Analogues on Hepatitis B Virus DNA Synthesis in HB611 Cells

1994 ◽  
Vol 5 (2) ◽  
pp. 57-63 ◽  
Author(s):  
T. Yokota ◽  
K. Konno ◽  
S. Shigeta ◽  
A. Holy ◽  
J. Balzarini ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Hbv Dna ◽  
Inhibitory Effects ◽  
B Virus ◽  
Acyclic Nucleoside ◽  
Cellular Dna ◽  
Acyclic Nucleoside Phosphonate

By using an assay system based on a human hepatoblastoma cell line (HB611) that continuously synthesizes hepatitis B virus (HBV) DNA, 56 acyclic nucleoside phosphonate analogues were examined for their inhibitory effects on HBV DNA synthesis. The following compounds were found to inhibit HBV DNA synthesis at concentrations that were significantly lower than their minimum cytotoxic concentrations; 9-(2-phosphonylmethoxyethyl)adenine (PMEA), 9-(2-phosphonylmethoxyethyl) guanine(PMEG), 9-(2-phosphonylmethoxyethyl) guanine ethyl ester (PMEGEE), 9 - (2 - phosphonylmethoxyethyl) - 1 - deazaadenine (PMEC1A), 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP), ( S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), 9-(3-isopropoxy-2-phosphonylmethoxypropyl)adenine (IPPMPA), 9-( RS)-(2-phosphonylmethoxypropyl)adenine (PMPA) and 9-(3-hydroxy-2-phosphonylmethoxypropyl)-2, 6-diaminopurine (HPMPDAP). The most selective compounds (with indexes greater than 100) were PMEDAP, PMEA, IPPMPA, and PMPA. Acyclic pyrimidine nucleoside phosphonate analogues did not prove markedly selective as anti-HBV agents. Diphosphoryl derivatives of some acyclic purine nucleoside phos-phonates (i.e. PMEA, PMEDAP, HPMPA) were prepared. They proved inhibitory to HBV DNA polymerase but not cellular DNA polymerase α.

scholarly journals Residues Arg703, Asp777, and Arg781 of the RNase H Domain of Hepatitis B Virus Polymerase Are Critical for Viral DNA Synthesis

2013 ◽  
Vol 88 (1) ◽  
pp. 154-163 ◽  
Author(s):  
C. Ko ◽  
Y.-C. Shin ◽  
W.-J. Park ◽  
S. Kim ◽  
J. Kim ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Synthesis ◽  
Rnase H ◽  
Viral Dna ◽  
B Virus

scholarly journals Three Novel cis-Acting Elements Required for Efficient Plus-Strand DNA Synthesis of the Hepatitis B Virus Genome

2004 ◽  
Vol 78 (14) ◽  
pp. 7455-7464 ◽  
Author(s):  
Jehan Lee ◽  
Myeong-Kyun Shin ◽  
Hye-Jin Lee ◽  
Gyesoon Yoon ◽  
Wang-Shick Ryu
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Synthesis ◽  
Virus Genome ◽  
Complex Nature ◽  
Minus Strand ◽  
Cis Acting ◽  
Donor And Acceptor ◽  
B Virus ◽  
Template Switches

ABSTRACT Synthesis of the relaxed-circular (RC) DNA genomes of hepadnaviruses by reverse transcriptase involves two template switches during plus-strand DNA synthesis. These template switches require repeat sequences (so-called donor and acceptor sites) between which a complementary strand of nucleic acid is transferred. To determine cis-acting elements apart from the donor and acceptor sites that are required for plus-strand RC DNA synthesis by hepatitis B virus (HBV), a series of mutants bearing a small deletion were made and analyzed for their impact on the viral genome synthesis. We found three novel cis-acting elements in the HBV genome: one element, located in the middle of the minus strand, is indispensable, whereas the other two elements, located near either end of the minus strand, contribute modestly to the plus-strand RC DNA synthesis. The data indicated that the first element facilitates plus-strand RNA primer translocation or subsequent elongation during plus-strand RC DNA synthesis, while the last two elements, although distantly located on the minus strand, act at multiple steps to promote plus-strand RC DNA synthesis. The necessity of multiple cis-acting elements on the minus-strand template reflects the complex nature of hepadnavirus reverse transcription.

scholarly journals Hepatitis B e antigen, DNA polymerase activity, and infection of household contacts with hepatitis B virus

1979 ◽  
Vol 76 (6) ◽  
pp. 1319-1325 ◽  
Author(s):  
Robert P. Perrillo ◽  
Lawrence Gelb ◽  
Carolyn Campbell ◽  
Wanda Wellinghoff ◽  
Frank R. Ellis ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Hepatitis B E Antigen ◽  
Household Contacts ◽  
B Virus

scholarly journals Entecavir for Treatment of Hepatitis B Virus Displays No In Vitro Mitochondrial Toxicity or DNA Polymerase Gamma Inhibition

2007 ◽  
Vol 52 (2) ◽  
pp. 598-605 ◽  
Author(s):  
Charles E. Mazzucco ◽  
Robert K. Hamatake ◽  
Richard J. Colonno ◽  
Daniel J. Tenney
Keyword(s):  
Mitochondrial Dna ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Reverse Transcriptase ◽  
Dna Polymerase ◽  
Mitochondrial Proteins ◽  
Mitochondrial Toxicity ◽  
Chronic Hepatitis B Virus ◽  
B Virus

ABSTRACT Therapy with nucleoside reverse transcriptase inhibitors (NRTIs) can be associated with mitochondrial toxicity. In vitro studies have been used to predict the predisposition for and characterize the mechanisms causing mitochondrial toxicity. Entecavir (ETV) is an approved deoxyguanosine nucleoside for the treatment of chronic hepatitis B virus (HBV) infection that exhibits potent activity against viral reverse transcriptase. We assessed the potential for mitochondrial toxicity of ETV in long-term cultures of HepG2 hepatoma cells by measuring mitochondrial function (through lactate secretion), levels of mitochondrial DNA (mtDNA), and levels of mitochondrial proteins COX II and COX IV. Furthermore, we tested the activity of ETV-triphosphate (ETV-TP) against mitochondrial DNA polymerase γ (Pol γ) in vitro. ETV concentrations as high as 100 times the maximal clinical exposure (C max) did not affect cell proliferation, levels of lactate, mitochondrial DNA, or mitochondrial proteins throughout the 15-day culture. The lack of mitochondrial toxicity was consistent with the finding that ETV-TP was not recognized by mitochondrial DNA Pol γ and failed to be incorporated into DNA or inhibit the polymerase assay at the highest levels tested, 300 μM. Combinations of ETV with each of the other HBV NRTI antivirals, adefovir, tenofovir, and lamivudine at 10 times their respective C max levels also failed to result in cellular or mitochondrial toxicity. In summary, cell culture and enzymatic studies yielded no evidence that would predict mitochondrial toxicity of ETV at exposure levels in excess of those expected to be achieved clinically.

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