scholarly journals Alphaherpesvirus Major Tegument Protein VP22: Its Precise Function in the Viral Life Cycle

2020 ◽  
Vol 11 ◽  
Author(s):  
Liping Wu ◽  
Anchun Cheng ◽  
Mingshu Wang ◽  
Renyong Jia ◽  
Qiao Yang ◽  
...  
Keyword(s):  
Life Cycle ◽  
Viral Life Cycle ◽  
Tegument Protein ◽  
Protein Vp22

scholarly journals Nucleosome Positioning on Episomal Human Papillomavirus DNA in Cultured Cells

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 772
Author(s):  
Isao Murakami ◽  
Takashi Iwata ◽  
Tohru Morisada ◽  
Kyoko Tanaka ◽  
Daisuke Aoki
Keyword(s):  
Life Cycle ◽  
Cultured Cells ◽  
Basal Layer ◽  
Nucleosome Positioning ◽  
Viral Life Cycle ◽  
Human Papillomaviruses ◽  
Host Cells ◽  
Micrococcal Nuclease ◽  
Hpv Dna ◽  
Dna Replication And Repair

Several human papillomaviruses (HPV) are associated with the development of cervical carcinoma. HPV DNA synthesis is increased during the differentiation of infected host keratinocytes as they migrate from the basal layer of the epithelium to the spinous layer, but the molecular mechanism is unclear. Nucleosome positioning affects various cellular processes such as DNA replication and repair by permitting the access of transcription factors to promoters to initiate transcription. In this study, nucleosome positioning on virus chromatin was investigated in normal immortalized keratinocytes (NIKS) stably transfected with HPV16 or HPV18 genomes to determine if there is an association with the viral life cycle. Micrococcal nuclease-treated DNA analyzed by Southern blotting using probes against HPV16 and HPV18 and quantified by nucleosome scanning analysis using real-time PCR revealed mononucleosomal-sized fragments of 140–200 base pairs that varied in their location within the viral genome according to whether the cells were undergoing proliferation or differentiation. Notably, changes in the regions around nucleotide 110 in proliferating and differentiating host cells were common to HPV16 and HPV18. Our findings suggest that changes in nucleosome positions on viral DNA during host cell differentiation is an important regulatory event in the viral life cycle.

scholarly journals A Comprehensive, Flexible Collection of SARS-CoV-2 Coding Regions

2020 ◽  
Vol 10 (9) ◽  
pp. 3399-3402 ◽  
Author(s):  
Dae-Kyum Kim ◽  
Jennifer J Knapp ◽  
Da Kuang ◽  
Aditya Chawla ◽  
Patricia Cassonnet ◽  
...  
Keyword(s):  
Life Cycle ◽  
Viral Life Cycle ◽  
Coding Sequences ◽  
Coding Regions ◽  
Global Pandemic ◽  
The World ◽  
Molecular Studies ◽  
Widespread Availability ◽  
Rapid Transfer

Abstract The world is facing a global pandemic of COVID-19 caused by the SARS-CoV-2 coronavirus. Here we describe a collection of codon-optimized coding sequences for SARS-CoV-2 cloned into Gateway-compatible entry vectors, which enable rapid transfer into a variety of expression and tagging vectors. The collection is freely available. We hope that widespread availability of this SARS-CoV-2 resource will enable many subsequent molecular studies to better understand the viral life cycle and how to block it.

scholarly journals Roles of the Picornaviral 3C Proteinase in the Viral Life Cycle and Host Cells

Viruses ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 82 ◽  
Author(s):  
Di Sun ◽  
Shun Chen ◽  
Anchun Cheng ◽  
Mingshu Wang
Keyword(s):  
Life Cycle ◽  
Viral Life Cycle ◽  
Host Cells

scholarly journals AdEasy-based cloning system to generate tropism expanded replicating adenoviruses expressing transgenes late in the viral life cycle

Gene Therapy ◽  
2005 ◽  
Vol 12 (17) ◽  
pp. 1347-1352 ◽  
Author(s):  
M Lie-A-Ling ◽  
C T Bakker ◽  
J G Wesseling ◽  
P J Bosma
Keyword(s):  
Life Cycle ◽  
Viral Life Cycle ◽  
Cloning System

Molecular Docking of Azithromycin, Ritonavir, Lopinavir, Oseltamivir, Ivermectin and Heparin Interacting with Coronavirus Disease 2019 Main and Severe Acute Respiratory Syndrome Coronavirus-2 3C-Like Proteases

2021 ◽  
Vol 21 (4) ◽  
pp. 2075-2089
Author(s):  
Tiago da Silva Arouche ◽  
Anderson Yuri Martins ◽  
Teodorico de Castro Ramalho ◽  
Raul Nunes Carvalho Júnior ◽  
Fabio Luiz Paranhos Costa ◽  
...  
Keyword(s):  
Life Cycle ◽  
Viral Life Cycle ◽  
Stable Complex ◽  
Viral Agent ◽  
Main Protease ◽  
Wide Range ◽  
Approved Drugs ◽  
Pharmacologically Active ◽  
3Cl Protease

In the current pandemic situation raised due to COVID-19, drug reuse is emerging as the first line of treatment. The viral agent that causes this highly contagious disease and the acute respiratory syndrome coronavirus (SARS-CoV) share high nucleotide similarity. Therefore, it is structurally expected that many existing viral targets are similar to the first SARS-CoV, probably being inhibited by the same compounds. Here, we selected two viral proteins based on their vital role in the viral life cycle: Structure of the main protease SARS-CoV-2 and the structural base of the SARS-CoV-2 protease 3CL, both supporting the entry of the virus into the human host. The approved drugs used were azithromycin, ritonavir, lopinavir, oseltamivir, ivermectin and heparin, which are emerging as promising agents in the fight against COVID-19. Our hypothesis behind molecular coupling studies is to determine the binding affinities of these drugs and to identify the main amino acid residues that play a fundamental role in their mechanism of action. Additional studies on a wide range of FDA-approved drugs, including a few more protein targets, molecular dynamics studies, in vitro and biological in vivo evaluation are needed to identify combination therapy targeted at various stages of the viral life cycle. In our experiment in silico, based mainly on the molecular coupling approach, we investigated six different types of pharmacologically active drugs, aiming at their potential application alone or in combination with the reuse of drugs. The ligands showed stable conformations when analyzing the affinity energy in both proteases: ivermectin forming a stable complex with the two proteases with values −8.727 kcal/mol for Main Protease and −9.784 kcal/mol for protease 3CL, Heparin with values of −7.647 kcal/mol for the Main protease and −7.737 kcal/mol for the 3CL protease. Both conform to the catalytic site of the proteases. Our studies can provide an insight into the possible interactions between ligands and receptors, through better conformation. The ligands ivermectin, heparin and ritonavir showed stable conformations. Our in-silica docking data shows that the drugs we have identified can bind to the binding compartment of both proteases, this strongly supports our hypothesis that the development of a single antiviral agent targeting Main protease, or 3CL protease, or an agent used in combination with other potential therapies, it could provide an effective line of defense against diseases associated with coronaviruses.

scholarly journals Retroviral Restriction Factors Fv1 and TRIM5α Act Independently and Can Compete for Incoming Virus before Reverse Transcription

2006 ◽  
Vol 80 (5) ◽  
pp. 2100-2105 ◽  
Author(s):  
Luca D. Passerini ◽  
Zuzana Keckesova ◽  
Greg J. Towers
Keyword(s):  
Life Cycle ◽  
Reverse Transcription ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Viral Life Cycle ◽  
Human Cells ◽  
Restriction Factors ◽  
Retroviral Infection ◽  
The Relationship ◽  
Murine Leukemia

ABSTRACT The restriction factors Fv1 and TRIM5α provide dominant blocks to retroviral infection, targeting incoming capsids at a postentry, preintegration step. They both restrict N-tropic murine leukemia virus with similar specificity yet act at different points in the viral life cycle. TRIM5α-restricted virus is usually unable to reverse transcribe, whereas Fv1-restricted virus reverse transcribes normally. Here we investigate the relationship between these two restriction factors by expressing Fv1 alleles in human cells. We demonstrate that Fv1 is able to compete with TRIM5α for virus before reverse transcription. In human cells expressing Fv1b, N-tropic restricted virus becomes less infectious but reverse transcribes more efficiently, indicating competition between the two antiviral molecules and protection of the virus from TRIM5α by Fv1. Our findings suggest that, like TRIM5α, Fv1 interacts with virus before reverse transcription, but the consequences of this interaction are not realized until a later stage of the life cycle. We also demonstrate that Fv1 is functionally independent of TRIM5α when expressed in human cells.

scholarly journals An Absolutely Conserved Tryptophan in the Stem of the Envelope Protein E of Flaviviruses Is Essential for the Formation of Stable Particles

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1727
Author(s):  
Iris Medits ◽  
Franz X. Heinz ◽  
Karin Stiasny
Keyword(s):  
Life Cycle ◽  
Envelope Protein ◽  
Transmembrane Domain ◽  
Viral Life Cycle ◽  
Compensatory Mutation ◽  
Sequence Element ◽  
Conserved Sequence ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Stable Particles

The major envelope protein E of flaviviruses contains an ectodomain that is connected to the transmembrane domain by the so-called “stem” region. In mature flavivirus particles, the stem is composed of two or three mostly amphipathic α-helices and a conserved sequence element (CS) with an undefined role in the viral life cycle. A tryptophan is the only residue within this region which is not only conserved in all vector-borne flaviviruses, but also in the group with no known vector. We investigated the importance of this residue in different stages of the viral life cycle by a mutagenesis-based approach using tick-borne encephalitis virus (TBEV). Replacing W421 by alanine or histidine strongly reduced the release of infectious virions and their thermostability, whereas fusion-related entry functions and virus maturation were still intact. Serial passaging of the mutants led to the emergence of a same-site compensatory mutation to leucine that largely restored these properties of the wildtype. The conserved tryptophan in CS (or another big hydrophobic amino acid at the same position) is thus essential for the assembly and infectivity of flaviviruses by being part of a network required for conferring stability to infectious particles.

scholarly journals The heat shock protein 70 family members HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle (144.1)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Ronik Khachatoorian ◽  
Ekambaram Ganapathy ◽  
Yasaman Ahmadieh ◽  
Nicole Wheatley ◽  
Christopher Sundberg ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Family Members ◽  
Viral Life Cycle
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