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
Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 772
Author(s):  
Isao Murakami ◽  
Takashi Iwata ◽  
Tohru Morisada ◽  
Kyoko Tanaka ◽  
Daisuke Aoki

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luis Fernando Saraiva Macedo Timmers ◽  
Julia Vasconcellos Peixoto ◽  
Rodrigo Gay Ducati ◽  
José Fernando Ruggiero Bachega ◽  
Leandro de Mattos Pereira ◽  
...  

AbstractDue to the high rate of transmissibility, Brazil became the new COVID-19 outbreak epicenter and, since then, is being monitored to understand how SARS-CoV-2 mutates and spreads. We combined genomic and structural analysis to evaluate genomes isolated from different regions of Brazil and show that the most prevalent mutations were located in the S, N, ORF3a and ORF6 genes, which are involved in different stages of viral life cycle and its interaction with the host cells. Structural analysis brought to light the positions of these mutations on protein structures, contributing towards studies of selective structure-based drug discovery and vaccine development.


2021 ◽  
Author(s):  
Mei Dang ◽  
Jianxing Song

SARS-CoV-2 is the coronavirus causing the catastrophic pandemic which already led to >120 millions of infections and >2.6 millions of deaths. Hydroxychloroquine (HCQ) has been shown to own promising potential in clinically combating SARS-CoV-2 but the underlying mechanisms still remain almost unknown. So far, all action sites are proposed on the host cells, and in particular no specific viral target protein has been experimentally identified. In this study, by use of DIC microscopy and NMR spectroscopy, for the first time we have decoded that HCQ specifically binds to both N-terminal domain (NTD) and C-terminal domain (CTD) of SARS-CoV-2 nucleocapsid (N) protein to inhibit their interactions with nucleic acids (NAs), as well as to disrupt its NA-induced liquid-liquid phase separation (LLPS) essential for the viral life cycle including the package of gRNA and N protein into new virions. These results suggest that HCQ may achieve its anti-SARS-CoV-2 activity by interfering in several key steps of the viral life cycle. The study not only provides a structural basis for the anti-SARS-CoV-2 activity of HCQ, but also indicates that SARS-CoV-2 N protein and its LLPS represent key targets for further optimization and development of anti-SARS-CoV-2 drugs.


2021 ◽  
Author(s):  
Isao Murakami ◽  
Takashi Iwata ◽  
Tohru Morisada ◽  
Kyoko Tanaka ◽  
Daisuke Aoki

Abstract 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 change in nucleosome position on viral DNA during host cell differentiation is an important regulatory event in the viral life cycle.


2021 ◽  
Author(s):  
Jianxing Song

SARS-CoV-2 is the coronavirus causing the catastrophic pandemic which already led to >120 millions of infections and >2.6 millions of deaths. Hydroxychloroquine (HCQ) has been shown to own promising potential in clinically combating SARS-CoV-2 but the underlying mechanisms still remain almost unknown. So far, all action sites are proposed on the host cells, and in particular no specific viral target protein has been experimentally identified. In this study, by use of DIC microscopy and NMR spectroscopy, for the first time we have decoded that HCQ specifically binds to both N-terminal domain (NTD) and C-terminal domain (CTD) of SARS-CoV-2 nucleocapsid (N) protein to inhibit their interactions with nucleic acids (NAs), as well as to disrupt its NA-induced liquid- liquid phase separation (LLPS) essential for the viral life cycle including the package of gRNA and N protein into new virions. These results suggest that HCQ may achieve its anti-SARS-CoV-2 activity by interfering in several key steps of the viral life cycle. The study not only provides a structural basis for the anti-SARS-CoV-2 activity of HCQ, but also indicates that SARS-CoV-2 N protein and its LLPS represent key targets for further optimization and development of anti-SARS-CoV-2 drugs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Monika Kowalczyk ◽  
Aleksandra Golonko ◽  
Renata Świsłocka ◽  
Monika Kalinowska ◽  
Monika Parcheta ◽  
...  

The coronavirus pandemic (SARS CoV-2) that has existed for over a year, constantly forces scientists to search for drugs against this virus. In silico research and selected experimental data have shown that compounds of natural origin such as phenolic acids and flavonoids have promising antiviral potential. Phenolic compounds inhibit multiplication of viruses at various stages of the viral life cycle, e.g., attachment (disturbance of the interaction between cellular and viral receptors), penetration (inhibition of viral pseudo-particle fusion to the host membrane), replication (inhibition of integrase and 3C-like protease), assembly and maturation (inhibition of microsomal triglyceride transfer protein (MTP) activity hydrolysis) and release (inhibition of secretion of apolipoprotein B (apoB) from infected cells). Phenolic compounds also indirectly influence on the viral life cycle by affecting the host cell’s biochemical processes that viruses use for their own benefit. Phenolic compounds may inhibit the proteasomes and cellular deubiquitinating activity that causes an increase in the ubiquitinated proteins level in host cells. This, in turn, contributes to the lowering the available ubiquitin molecules that viruses could use for their own replication. One of the drug design strategy for the treatment of viral diseases may be an enhancement of the antiviral properties of phenolic compounds by metal complexation. Many studies have shown that the presence of a metal ion in the structure can significantly affect the affinity of the compound to key structural elements of the SARS CoV-2, such as Mpro protease, RNA-dependent RNA polymerase (RdRp) and spike protein. We believe that in the era of coronavirus pandemic, it is necessary to reconsider the search for therapeutics among well-known compounds of plant origin and their metal complexes.


2020 ◽  
Vol 10 (9) ◽  
pp. 3399-3402 ◽  
Author(s):  
Dae-Kyum Kim ◽  
Jennifer J Knapp ◽  
Da Kuang ◽  
Aditya Chawla ◽  
Patricia Cassonnet ◽  
...  

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.


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

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 ◽  
...  

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.


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