scholarly journals RapidIn VitroEvolution of Human Cytomegalovirus UL56 Mutations That Confer Letermovir Resistance

2015 ◽  
Vol 59 (10) ◽  
pp. 6588-6593 ◽  
Author(s):  
Sunwen Chou
Keyword(s):  
Normal Growth ◽  
Low Grade ◽  
Close Monitoring ◽  
Wild Type ◽  
Active Infection ◽  
Genetic Barrier ◽  
Phase 3 ◽  
Viral Growth ◽  
Recombinant Viruses ◽  
Additional Resistance

ABSTRACTLetermovir (LMV) is an experimental cytomegalovirus terminase inhibitor undergoing phase 3 clinical trials. Viral mutations have been described at UL56 codons 231 to 369 that confer widely variable levels of LMV resistance. In this study, 15 independent experiments propagating an exonuclease mutant viral strain in escalating LMV concentrations replicated 6 of the 7 published UL56 mutations and commonly elicited additional resistance-conferring mutations at UL56 codons 231, 236, 237, 244, 257, 261, 325, and 329. Mutations were first detected earlier in LMV (median, 3 passages) than in 8 parallel experiments with foscarnet (median, 15 passages). As LMV concentrations increased, the typical initial UL56 change F261L, which confers low-grade resistance, combined or was replaced with mutations conferring higher-grade resistance, eventually enabling normal viral growth in 30 μM LMV (>5,000-fold the 50% effective concentration [EC50] for the wild type). At high LMV concentrations, the UL56 changes C325F/R were commonly detected, as well as a combination of changes at codons 236, 257, 329, and/or 369. Recombinant viruses containing individual UL56 mutations and combinations were constructed to confirm their resistance phenotypes and normal growth in cell culture. Several double and triple mutants showed much higher LMV resistance than the respective single mutants, particularly those including changes at both codons 236 and 257. The multiplicity of pathways to high-grade LMV resistance with minimal viral growth impact suggests a low viral genetic barrier and the need for close monitoring during treatment of active infection.

scholarly journals P04.16 TP53 mutations in codon 273 is predictive of overall survival in astrocytoma patients

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii32-iii32
Author(s):  
H Noor ◽  
R Rapkins ◽  
K McDonald
Keyword(s):  
Overall Survival ◽  
Tp53 Mutation ◽  
Progression Free Survival ◽  
Low Grade Glioma ◽  
Low Grade ◽  
Wild Type ◽  
Mutation Status ◽  
Free Survival ◽  
Tp53 Mutations ◽  
Fresh Frozen

Abstract BACKGROUND Tumour Protein 53 (TP53) is a tumour suppressor gene that is mutated in at least 50% of human malignancies. The prevalence of TP53 mutation is much higher in astrocytomas with reports of up to 75% TP53 mutant cases. Rare cases of TP53 mutation also exist in oligodendroglial tumours (10–13%). P53 pathway is therefore an important factor in low-grade glioma tumorigenesis. Although the prognostic impact of TP53 mutations has been studied previously, no concrete concordance were reached between the studies. In this study, we investigated the prognostic effects of TP53 mutation in astrocytoma and oligodendroglioma. MATERIAL AND METHODS A cohort of 65 matched primary and recurrent fresh frozen tumours were sequenced to identify hotspot exons of TP53 mutation. Exons 1 to 10 were sequenced and pathogenic mutations were mostly predominant between Exons 4 and 8. The cohort was further expanded with 78 low grade glioma fresh frozen tissues and hotspot exons were sequenced. Selecting only the primary tumour from 65 matched tumours, a total of 50 Astrocytoma cases and 51 oligodendroglioma cases were analysed for prognostic effects of TP53. Only pathogenic TP53 mutations confirmed through COSMIC and NCBI databases were included in the over survival and progression-free survival analysis. RESULTS 62% (31/50) of astrocytomas and 16% (8/51) of oligodendrogliomas harboured pathogenic TP53 mutations. Pathogenic hotspot mutations in codon 273 (c.817 C>T and c.818 G>A) was prevalent in astrocytoma with 58% (18/31) of tumours with these mutations. TP53 mutation status was maintained between primary and recurrent tumours in 93% of cases. In astrocytoma, overall survival of TP53 mutant patients was longer compared to TP53 wild-type patients (p<0.01) but was not significant after adjusting for age, gender, grade and IDH1 mutation status. In contrast, astrocytoma patients with specific TP53 mutation in codon 273 showed significantly better survival compared to other TP53 mutant and TP53 wild-type patients combined (p<0.01) in our multivariate analysis. Time to first recurrence (progression-free survival) of TP53 mutant patients was significantly longer than TP53 wild-type patients (p<0.01) after adjustments were made, while TP53 mutation in codon 273 was not prognostic for progression-free survival. In oligodendroglioma patients, TP53 mutations did not significantly affect overall survival and progression-free survival. CONCLUSION In agreement with others, TP53 mutation is more prevalent in Astrocytoma and mutations in codon 273 are significantly associated with longer survival.

scholarly journals Deletion of znuA Virulence Factor Attenuates Brucella abortus and Confers Protection against Wild-Type Challenge

2006 ◽  
Vol 74 (7) ◽  
pp. 3874-3879 ◽  
Author(s):  
Xinghong Yang ◽  
Todd Becker ◽  
Nancy Walters ◽  
David W. Pascual
Keyword(s):  
Brucella Abortus ◽  
Deletion Mutant ◽  
Pasteurella Multocida ◽  
Brucella Melitensis ◽  
Normal Growth ◽  
Wild Type ◽  
Minimal Growth ◽  
M Genome ◽  
S19 Vaccine ◽  
Knockout Mutation

ABSTRACT znuA is known to be an important factor for survival and normal growth under low Zn2+ concentrations for Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida. We hypothesized that the znuA gene present in Brucella melitensis 16 M would be similar to znuA in B. abortus and questioned whether it may also be an important factor for growth and virulence of Brucella abortus. Using the B. melitensis 16 M genome sequence, primers were designed to construct a B. abortus deletion mutant. A znuA knockout mutation in B. abortus 2308 (ΔznuA) was constructed and found to be lethal in low-Zn2+ medium. When used to infect macrophages, ΔznuA B. abortus showed minimal growth. Further study with ΔznuA B. abortus showed that its virulence in BALB/c mice was attenuated, and most of the bacteria were cleared from the spleen within 8 weeks. Protection studies confirmed the ΔznuA mutant as a potential live vaccine, since protection against wild-type B. abortus 2308 challenge was as effective as that obtained with the RB51 or S19 vaccine strain.

scholarly journals exrB: amalB-linked gene inEscherichia coliB involved in sensitivity to radiation and filament formation

1974 ◽  
Vol 23 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Joseph Greenberg ◽  
Leonard J. Berends ◽  
John Donch ◽  
Michael H. L. Green
Keyword(s):  
Escherichia Coli ◽  
Normal Growth ◽  
Filament Formation ◽  
Wild Type ◽  
Sensitive Mutant ◽  
Γ Radiation ◽  
Linked Gene ◽  
Derivatives Of

SUMMARYPAM 26, a radiation-sensitive mutant ofEscherichia colistrain B, is described. Its properties are attributable to a mutation in a gene,exrB, which is cotransducible withmalB. It differs fromuvrA(alsomalB-linked) derivatives of strain B in being sensitive to 1-methyl-3-nitro-1-nitroso-guanidine and γ-radiation, and in being able to reactivate UV-irradiated phage T3. It differs fromexrA(alsomalB-linked) derivatives of strain B in forming filaments during the course of normal growth as well as after irradiation. WhenexrBwas transduced into a K12 (lon+) strain, filaments did not form spontaneously. Three-point transductions established the order of markers asmet A malB exrB. Based on an analysis of the frequency of wild-type recombinants in a reciprocal transduction betweenexrAandexrBstrains, it was inferred that they are not isogenic and that the order of markers ismalB exrA exrB.

scholarly journals Involvement of the N-Terminal Deubiquitinating Protease Domain of Human Cytomegalovirus UL48 Tegument Protein in Autoubiquitination, Virion Stability, and Virus Entry

2016 ◽  
Vol 90 (6) ◽  
pp. 3229-3242 ◽  
Author(s):  
Young-Eui Kim ◽  
Se Eun Oh ◽  
Ki Mun Kwon ◽  
Chan Hee Lee ◽  
Jin-Hyun Ahn
Keyword(s):  
Human Cytomegalovirus ◽  
Virus Entry ◽  
Terminal Region ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Viral Growth ◽  
Internal Region ◽  
Deubiquitinating Protease

ABSTRACTHuman cytomegalovirus (HCMV) protein pUL48 is closely associated with the capsid and has a deubiquitinating protease (DUB) activity in its N-terminal region. Although this DUB activity moderately increases virus replication in cultured fibroblast cells, the requirements of the N-terminal region of pUL48 in the viral replication cycle are not fully understood. In this study, we characterized the recombinant viruses encoding UL48(ΔDUB/NLS), which lacks the DUB domain and the adjacent nuclear localization signal (NLS), UL48(ΔDUB), which lacks only the DUB, and UL48(Δ360–1200), which lacks the internal region (amino acids 360 to 1200) downstream of the DUB/NLS. While ΔDUB/NLS and Δ360–1200 mutant viruses did not grow in fibroblasts, the ΔDUB virus replicated to titers 100-fold lower than those for wild-type virus and showed substantially reduced viral gene expression at low multiplicities of infection. The DUB domain contained ubiquitination sites, and DUB activity reduced its own proteasomal degradation intrans. Deletion of the DUB domain did not affect the nuclear and cytoplasmic localization of pUL48, whereas the internal region (360–1200) was necessary for cytoplasmic distribution. In coimmunoprecipitation assays, pUL48 interacted with three tegument proteins (pUL47, pUL45, and pUL88) and two capsid proteins (pUL77 and pUL85) but the DUB domain contributed to only pUL85 binding. Furthermore, we found that the ΔDUB virus showed reduced virion stability and less efficiently delivered its genome into the cell than the wild-type virus. Collectively, our results demonstrate that the N-terminal DUB domain of pUL48 contributes to efficient viral growth by regulating its own stability and promoting virion stabilization and virus entry.IMPORTANCEHCMV pUL48 and its herpesvirus homologs play key roles in virus entry, regulation of immune signaling pathways, and virion assembly. The N terminus of pUL48 contains the DUB domain, which is well conserved among all herpesviruses. Although studies using the active-site mutant viruses revealed that the DUB activity promotes viral growth, the exact role of this region in the viral life cycle is not fully understood. In this study, using the mutant virus lacking the entire DUB domain, we demonstrate that the DUB domain of pUL48 contributes to viral growth by regulating its own stability via autodeubiquitination and promoting virion stability and virus entry. This report is the first to demonstrate the characteristics of the mutant virus with the entire DUB domain deleted, which, along with information on the functions of this region, is useful in dissecting the functions associated with pUL48.

scholarly journals The Role of Extent of Resection in IDH1 Wild-Type or Mutant Low-Grade Gliomas

Neurosurgery ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. 808-814 ◽  
Author(s):  
Toral Patel ◽  
Evan D Bander ◽  
Rachael A Venn ◽  
Tiffany Powell ◽  
Gustav Young-Min Cederquist ◽  
...  
Keyword(s):  
Cox Regression ◽  
Extent Of Resection ◽  
World Health ◽  
Low Grade ◽  
Wild Type ◽  
Who Grade ◽  
Cox Regression Analysis ◽  
Low Grade Gliomas ◽  
Grade Ii ◽  
The Impact

Abstract BACKGROUND Maximizing extent of resection (EOR) improves outcomes in adults with World Health Organization (WHO) grade II low-grade gliomas (LGG). However, recent studies demonstrate that LGGs bearing a mutation in the isocitrate dehydrogenase 1 (IDH1) gene are a distinct molecular and clinical entity. It remains unclear whether maximizing EOR confers an equivalent clinical benefit in IDH mutated (mtIDH) and IDH wild-type (wtIDH) LGGs. OBJECTIVE To assess the impact of EOR on malignant progression-free survival (MPFS) and overall survival (OS) in mtIDH and wtIDH LGGs. METHODS We performed a retrospective review of 74 patients with WHO grade II gliomas and known IDH mutational status undergoing resection at a single institution. EOR was assessed with quantitative 3-dimensional volumetric analysis. The effect of predictor variables on MPFS and OS was analyzed with Cox regression models and the Kaplan–Meier method. RESULTS Fifty-two (70%) mtIDH patients and 22 (30%) wtIDH patients were included. Median preoperative tumor volume was 37.4 cm3; median EOR of 57.6% was achieved. Univariate Cox regression analysis confirmed EOR as a prognostic factor for the entire cohort. However, stratifying by IDH status demonstrates that greater EOR independently prolonged MPFS and OS for wtIDH patients (hazard ratio [HR] = 0.002 [95% confidence interval {CI} 0.000-0.074] and HR = 0.001 [95% CI 0.00-0.108], respectively), but not for mtIDH patients (HR = 0.84 [95% CI 0.17-4.13] and HR = 2.99 [95% CI 0.15-61.66], respectively). CONCLUSION Increasing EOR confers oncologic and survival benefits in IDH1 wtLGGs, but the impact on IDH1 mtLGGs requires further study.

scholarly journals Evaluating the fitness of PA/I38T-substituted influenza A viruses with reduced baloxavir susceptibility in a competitive mixtures ferret model

2020 ◽  
Author(s):  
Leo YY Lee ◽  
Jie Zhou ◽  
Paulina Koszalka ◽  
Rebecca Frise ◽  
Rubaiyea Farrukee ◽  
...  
Keyword(s):  
Influenza A ◽  
Relative Fitness ◽  
Replication Capacity ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Widespread Occurrence ◽  
Host Fitness ◽  
Recombinant Viruses ◽  
Risk Patients ◽  
Virus Isolates

AbstractBaloxavir is approved in several countries for the treatment of uncomplicated influenza in otherwise-healthy and high-risk patients. Treatment-emergent viruses with reduced susceptibility to baloxavir have been detected in clinical trials, but the likelihood of widespread occurrence depends on replication capacity and onward transmission. We evaluated the fitness of A/H3N2 and A/H1N1pdm09 viruses with the polymerase acidic I38T-variant conferring reduced susceptibility to baloxavir relative to wild-type (WT) viruses, using a competitive mixture ferret model, recombinant viruses and patient-derived virus isolates. The A/H3N2 I38T virus showed a reduction in within-host fitness but comparable between-host fitness to the WT virus, while the A/H1N1pdm09 I38T virus had broadly similar within-host fitness but substantially lower between-host fitness. Although I38T viruses replicate and transmit between ferrets, our data suggest that viruses with this amino acid substitution have lower fitness relative to WT and this relative fitness cost was greater in A/H1N1pdm09 viruses than in A/H3N2 viruses.

scholarly journals MNB1 gene is involved in regulating the iron-deficiency stress response in Arabidopsis thaliana

2021 ◽  
Author(s):  
Hui Song ◽  
Feng Chen ◽  
Xi Wu ◽  
Min Hu ◽  
Qingliu Geng ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Arabidopsis Thaliana ◽  
Normal Growth ◽  
Developmental Changes ◽  
Fe Deficiency ◽  
Oxygen Species ◽  
Mineral Element ◽  
Wild Type ◽  
Transcription Level ◽  
Fe Uptake

Abstract Abstract Iron (Fe) is an indispensable mineral element for normal growth of plants. Fe deficiency induces a complex series of responses in plants, involving physiological and developmental changes, to increase Fe uptake from soil. However, the molecular mechanism involved in plant Fe-deficiency is not well understood. Here, we found that the MNB1 gene is involved in modulating Fe-deficiency response in Arabidopsis thaliana . The expression of MNB1 was inhabited by Fe-deficiency stress. Knockout of MNB1 led to enhanced Fe accumulation and tolerance, whereas the MNB1-overexpressing plants were sensitive to Fe-deficiency stress. Lower H 2 O 2 concentrations in mnb1 mutant plants were examined under Fe deficiency circumstances compared to wild-type. On the contray, higher H 2 O 2 concentrations were found in MNB1-overexpressing plants, which was adversely linked with malondialdehyde (MDA) concentrations. Furthermore, in mnb1 mutants, the transcription level of the Fe-uptake and translocation genes, FIT , IRT1 , FRO2 , Z IF , FRD3 , NAS4 , PYE and MYB72 , were considerably elevated during Fe-deficiency stress, resulting in higher Fe accumulation. Together, our findings show that the MNB1 gene negatively controls the Fe-deficiency response in Arabidopsis via modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling pathway, thereby affecting the expression of Fe-uptake and translocation genes.

scholarly journals A multicentre, prospective, randomised controlled trial to evaluate hexaminolevulinate photodynamic therapy (Cevira®) as a novel treatment in patients with high grade squamous intraepithelial lesion: APRICITY Phase 3 study protocol

2021 ◽  
Author(s):  
Fei Chen ◽  
Zoltán Novák ◽  
Christian Dannecker ◽  
Long Sui ◽  
Youzhong Zhang ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Low Grade ◽  
High Grade ◽  
Efficacy And Safety ◽  
Squamous Intraepithelial Lesion ◽  
Phase 3 ◽  
Link Type ◽  
Surgical Methods ◽  
Intraepithelial Lesion ◽  
Randomised Controlled

AbstractIntroductionHigh-risk human papilloma virus (HPV)-associated cervical cancer is the fourth most common cancer in women worldwide. Current treatments of high grade squamous intraepithelial lesion (HSIL) of the cervix are based on invasive surgical interventions, compromising cervical competence and functionality.ObjectiveAPRICITY is a multicentre, prospective, double-blind, randomised controlled Phase 3 study further evaluating the efficacy and safety of Cevira®, an integrated drug- and light-delivery device for hexaminolevulinate photodynamic therapy, which shows promise as a novel, non-invasive therapy for women with HSIL.Methods and analysisPatients with biopsy-confirmed HSIL histology are invited to participate in the study currently being conducted at 47 sites in China and 25 sites in Ukraine, Russia and European Union. The aim is to include at least 384 patients which will be randomised to either Cevira® or placebo group (2:1). All patients will be assessed 3 months after first treatment and a second treatment will be administered in patients who are HPV positive or have at least low grade squamous intraepithelial lesion (LSIL). Primary endpoint is the proportion of the responders at 6 months after first treatment. Secondary efficacy endpoints and safety endpoints will be assessed at 6 months, and data for secondary performance endpoints for Cevira® device will be collected at 3 months and 6 months, in case second treatment was administered. All patients in the Cevira® group will be enrolled in an open, long-term extension study following patients for further 6 months to collect additional efficacy and safety data (study extension endpoints).ConclusionDue to its non-invasiveness and convenient application, Cevira® may be a favourable alternative to surgical methods in treatment of patients with HSIL.Ethics and disseminationThe study was approved by the ethics committee of the Peking Union Medical College Hospital and Hannover Medical University, Germany. Findings will be disseminated through peer review publications and conference presentations.Trial registration numberclinicaltrials.govNCT04484415

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