Effect of 6S RNA on the transcription from σ and σ-specific promoters on linear DNA fragments

<p><b>Copyright information:</b></p><p>Taken from "Studies on the function of the riboregulator 6S RNA from : RNA polymerase binding, inhibition of transcription and synthesis of RNA-directed transcripts"</p><p></p><p>Nucleic Acids Research 2007;35(6):1885-1896.</p><p>Published online 1 Mar 2007</p><p>PMCID:PMC1874619.</p><p>© 2007 The Author(s)</p> Products from transcription reactions were separated on denaturing polyacrylamide gels and visualized by autoradiography. Reactions with the or P1 promoters are shown on the left or right side, respectively. The different holoenzymes employed (E70, E38) are indicated above the lanes. For each system the amount of 6S RNA present in the reaction was varied (lanes 1, 6, 11, 16: 0 nM, lane 2, 7, 12, 17: 10 nM, lane 3, 8, 13, 18: 50 nM, lane 4, 9, 14, 19: 100 nM, lane 5, 10, 15, 20: 250 nM). A 260 bp radiolabelled DNA fragment, indicated at the margin, was included as internal standard for quantification. The positions of the run-off transcripts for the (∼124 nt) and P1 (64 nt) promoters are marked. An arrow denotes a product that consistently arises when 6S RNA is incubated with RNA polymerase, even in the absence of any template DNA

Synthesis and Biological Characterization of Aryl Uracil Inhibitors of Hepatitis C Virus NS5B Polymerase: Discovery of ABT-072, a <i>trans</i>-Stilbene Analog with Good Oral Bioavailability

ABT-072 is a non-nucleoside HCV NS5B polymerase inhibitor that was discovered as part of a program to identify new direct-acting antivirals (DAAs) for the treatment of HCV infection. This compound was identified during a medicinal chemistry effort to improve on an original lead, inhibitor <b>1</b>, which we described in a previous publication. Replacement of the amide linkage in <b>1</b> with a trans-olefin resulted in improved compound permeability and solubility and provided much better pharmacokinetic properties in preclinical species. Replacement of the dihydrouracil in <b>1</b> with an N-linked uracil provided better potency in the genotype 1 replicon assay. Results from phase 1 clinical studies supported once-daily oral dosing with ABT-072 in HCV infected patients. A phase 2 clinical study that combined ABT-072 with the HCV protease inhibitor ABT-450 provided a sustained virologic response at 24 weeks after dosing (SVR₂₄) in 10 of 11 patients who received treatment

Synthesis and Biological Characterization of Aryl Uracil Inhibitors of Hepatitis C Virus NS5B Polymerase: Discovery of ABT-072, a <i>trans</i>-Stilbene Analog with Good Oral Bioavailability

ABT-072 is a non-nucleoside HCV NS5B polymerase inhibitor that was discovered as part of a program to identify new direct-acting antivirals (DAAs) for the treatment of HCV infection. This compound was identified during a medicinal chemistry effort to improve on an original lead, inhibitor <b>1</b>, which we described in a previous publication. Replacement of the amide linkage in <b>1</b> with a trans-olefin resulted in improved compound permeability and solubility and provided much better pharmacokinetic properties in preclinical species. Replacement of the dihydrouracil in <b>1</b> with an N-linked uracil provided better potency in the genotype 1 replicon assay. Results from phase 1 clinical studies supported once-daily oral dosing with ABT-072 in HCV infected patients. A phase 2 clinical study that combined ABT-072 with the HCV protease inhibitor ABT-450 provided a sustained virologic response at 24 weeks after dosing (SVR₂₄) in 10 of 11 patients who received treatment

Discovery of ABT-267, a Pan-Genotypic Inhibitor of HCV NS5A

We describe here <i>N</i>-phenylpyrrolidine-based inhibitors of HCV NS5A with excellent potency, metabolic stability, and pharmacokinetics. Compounds with 2<i>S</i>,5<i>S</i> stereochemistry at the pyrrolidine ring provided improved genotype 1 (GT1) potency compared to the 2<i>R</i>,5<i>R</i> analogues. Furthermore, the attachment of substituents at the 4-position of the central <i>N</i>-phenyl group resulted in compounds with improved potency. Substitution with <i>tert</i>-butyl, as in compound <b>38</b> (ABT-267), provided compounds with low-picomolar EC₅₀ values and superior pharmacokinetics. It was discovered that compound <b>38</b> was a pan-genotypic HCV inhibitor, with an EC₅₀ range of 1.7–19.3 pM against GT1a, -1b, -2a, -2b, -3a, -4a, and -5a and 366 pM against GT6a. Compound <b>38</b> decreased HCV RNA up to 3.10 log₁₀ IU/mL during 3-day monotherapy in treatment-naive HCV GT1-infected subjects and is currently in phase 3 clinical trials in combination with an NS3 protease inhibitor with ritonavir (r) (ABT-450/r) and an NS5B non-nucleoside polymerase inhibitor (ABT-333), with and without ribavirin

Highlights of the Structure–Activity Relationships of Benzimidazole Linked Pyrrolidines Leading to the Discovery of the Hepatitis C Virus NS5A Inhibitor Pibrentasvir (ABT-530)

Curative interferon and ribavirin sparing treatments for hepatitis C virus (HCV)-infected patients require a combination of mechanistically orthogonal direct acting antivirals. A shared component of these treatments is usually an HCV NS5A inhibitor. First generation FDA approved treatments, including the component NS5A inhibitors, do not exhibit equivalent efficacy against HCV virus genotypes 1–6. In particular, these first generation NS5A inhibitors tend to select for viral drug resistance. Ombitasvir is a first generation HCV NS5A inhibitor included as a key component of Viekira Pak for the treatment of patients with HCV genotype 1 infection. Since the launch of next generation HCV treatments, functional cure for genotype 1–6 HCV infections has been achieved, as well as shortened treatment duration across a wider spectrum of genotypes. In this paper, we show how we have modified the anchor, linker, and end-cap architecture of our NS5A inhibitor design template to discover a next generation NS5A inhibitor pibrentasvir (ABT-530), which exhibits potent inhibition of the replication of wild-type genotype 1–6 HCV replicons, as well as improved activity against replicon variants demonstrating resistance against first generation NS5A inhibitors