scholarly journals Paradox of Nonpathogenicity and Cytopathic Effects：Characterization of Regulator Tas in Foamy Virus Evolution and De-Ubiquitylation of Tas in Virus Duplication

2021 ◽  
Author(s):  
Wei Jie ◽  
Zhang Rui Fen ◽  
Song Jing ◽  
Wu Yan ◽  
Ma Yong Ping ◽  
...  
Keyword(s):  
Foamy Virus ◽  
Signal Pathways ◽  
Infection Level ◽  
Cytopathic Effects ◽  
Worldwide Distribution ◽  
Foamy Viruses ◽  
Protein Functions

Abstract Background: Foamy virus, which belong to the Spumaretrovirinae subfamily of Retroviridae, bridge the gap between Orthoretrovirinae and Hepadnaviridae, and display a long co-evolution with their hosts. Like other retroviruses, FVs encode a transactivator, Tas, which governs the levels of viral transcripts initiated through binding to the conserved promoters in 5’ long terminal repeat (LTR) and a unique internal promoter (IP). Unlike the other retrovirus, HIV, foamy viruses induced significant cytopathic effects in vitro, but has no significant disease association at the infection level in vivo. The characterization of regulator Tas in the Paradox of nonpathogenicity and cytopathic effects was still unknown.Results: Foamy virus separated from different hosts could form three groups which paralleled with the worldwide distribution of hosts due to geographical isolation. Although the physicochemical properties of different Tas were mainly in line with each other, the conserved motifs analyses still suggested divergences in protein functions. The proteins identified to interact with Tas of PFV, SFVora and SFVagm displayed that the three kinds of foamy viruses regulated different signal pathways and impacted virus-host immune interaction. Interestingly, predictions of interactional factors based on protein sequence showed USP7, a kind of deubiquitinating enzyme, could binding directly to Tas which led to its ubiquitin-dependent proteasome degradation. And this results also implyed that fomay virus could hijacked cytokine USP7 to stabilize the transcriptional activator Tas by de-ubiquitylation and thereby regulate the viral life cycle.Conclusion: Our experiments help to understand the survival strategy of foamy viruses in their hosts.

scholarly journals Acetylation of the foamy virus transactivator Tas by PCAF augments promoter-binding affinity and virus transcription

2007 ◽  
Vol 88 (1) ◽  
pp. 259-263 ◽  
Author(s):  
Jochen Bodem ◽  
Hans-Georg Kräusslich ◽  
Axel Rethwilm
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Foamy Virus ◽  
Effective Means ◽  
Histone Acetyltransferases ◽  
Virus Transcription ◽  
Foamy Viruses ◽  
Direct Gene

It was shown recently that retrovirus transactivators interact with transcriptional coactivators, such as histone acetyltransferases (HATs). Foamy viruses (FVs) direct gene expression from the long terminal repeat and from an internal promoter. The activity of both promoters is strictly dependent on the DNA-binding transactivator Tas. Recently, it was shown that Tas interacts with the HATs p300 and PCAF. Based on these findings, it is demonstrated here that PCAF has the ability to acetylate Tas in vitro and in vivo. Tas acetylation resulted in enhanced DNA binding to the virus promoters. In vitro transcription reactions on non-chromatinized template showed that only acetylated Tas enhanced transcription significantly. These results demonstrate that acetylation of the FV transactivator Tas may be an effective means to regulate virus transcription.

Physiological, morphological, and immunochemical parameters used for the characterization of clinical and environmental isolates ofAcanthamoeba

Parasitology ◽  
2012 ◽  
Vol 140 (3) ◽  
pp. 396-405 ◽  
Author(s):  
A. BECKER-FINCO ◽  
A. O. COSTA ◽  
S. K. SILVA ◽  
J. S. RAMADA ◽  
C. FURST ◽  
...  
Keyword(s):  
Comparative Evaluation ◽  
Polyclonal Antibodies ◽  
Protein Profiles ◽  
Environmental Isolates ◽  
Pathogenic Potential ◽  
Cytopathic Effects ◽  
Specific Proteins

SUMMARYThe factors that characterizeAcanthamoebastrains as harmless or potentially pathogenic have not been elucidated. Analysing thein vitroandin vivoparameters ofAcanthamoebasamples, including heat tolerance at temperatures close to that of the human body, cytopathic effects, and their ability to cause infections in animals, has been proposed to identify their pathogenic potential. Another promising criterion for differentiating strains is the analysis of their biochemical and immunochemical properties. In this study, a comparative evaluation between clinical and environmentalAcanthamoebaisolates was performed on the basis of physiological, morphological, and immunochemical criteria. Crude antigens were used to characterize the protein profiles by electrophoresis and immunize mice to produce polyclonal and monoclonal antibodies. The antibodies were characterized using ELISA, Western blotting, and immunofluorescence techniques. The results obtained with polyclonal antibodies suggest the presence of specific proteins for each studied isolate and co-reactive immunochemical profiles among conserved components. Ten monoclonal antibody clones were obtained; mAb3 recognized 3 out of 4 samples studied. The results of this study may help standardize criteria for identifying and characterizingAcanthamoebastrains. Taken together, our results support the view that a set of features may help differentiateAcanthamoebaspecies and isolates.

scholarly journals Distribution and Pathogenicity of Two Cutthroat Trout Virus (CTV) Genotypes in Canada

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1730
Author(s):  
Amy Long ◽  
Francis LeBlanc ◽  
Jean-René Arseneau ◽  
Nellie Gagne ◽  
Katja Einer-Jensen ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Cutthroat Trout ◽  
Open Reading Frames ◽  
Amplification Efficiency ◽  
Cytopathic Effects ◽  
Persistent Infections ◽  
In Vivo Characterization

The sole member of the Piscihepevirus genus (family Hepeviridae) is cutthroat trout virus (CTV) but recent metatranscriptomic studies have identified numerous fish hepevirus sequences including CTV-2. In the current study, viruses with sequences resembling both CTV and CTV-2 were isolated from salmonids in eastern and western Canada. Phylogenetic analysis of eight full genomes delineated the Canadian CTV isolates into two genotypes (CTV-1 and CTV-2) within the Piscihepevirus genus. Hepevirus genomes typically have three open reading frames but an ORF3 counterpart was not predicted in the Canadian CTV isolates. In vitro replication of a CTV-2 isolate produced cytopathic effects in the CHSE-214 cell line with similar amplification efficiency as CTV. Likewise, the morphology of the CTV-2 isolate resembled CTV, yet viral replication caused dilation of the endoplasmic reticulum lumen which was not previously observed. Controlled laboratory studies exposing sockeye (Oncorhynchus nerka), pink (O. gorbuscha), and chinook salmon (O. tshawytscha) to CTV-2 resulted in persistent infections without disease and mortality. Infected Atlantic salmon (Salmo salar) and chinook salmon served as hosts and potential reservoirs of CTV-2. The data presented herein provides the first in vitro and in vivo characterization of CTV-2 and reveals greater diversity of piscihepeviruses extending the known host range and geographic distribution of CTV viruses.

scholarly journals Identification and Functional Characterization of a High-Affinity Bel-1 DNA Binding Site Located in the Human Foamy Virus Internal Promoter

1998 ◽  
Vol 72 (1) ◽  
pp. 504-511 ◽  
Author(s):  
Yibin Kang ◽  
Wade S. Blair ◽  
Bryan R. Cullen
Keyword(s):  
Dna Binding ◽  
Binding Site ◽  
Foamy Virus ◽  
Promoter Element ◽  
Internal Promoter ◽  
Dna Binding Site ◽  
Foamy Viruses ◽  
Ltr Promoter

ABSTRACT The transcription of genes carried by primate foamy viruses is dependent on two distinct promoter elements. These are the long terminal repeat (LTR) promoter, which regulates expression of the viral structural proteins, and a second internal promoter, located towards the 3′ end of the env gene, that directs expression of the viral auxiliary proteins. One of these auxiliary proteins is a potent transcriptional transactivator, termed Bel-1 in human foamy virus (HFV) and Tas or Taf in the related simian foamy viruses, that is critical for foamy virus replication. Previously, it has been demonstrated that the LTR promoter element of HFV contains a DNA binding site for Bel-1 that is critical for transcriptional activation (F. He, W. S. Blair, J. Fukushima, and B. R. Cullen, J. Virol. 70:3902–3908, 1996). Here, we extended this earlier work by using methylation interference analysis to identify and characterize the Bel-1 DNA binding sites located in the HFV LTR and internal promoter elements. Based on these data, we propose a minimal, 25-bp DNA binding site for Bel-1, derived from the HFV internal promoter element, and show that this short DNA sequence mediates efficient Bel-1 binding both in vitro and in vivo. We further demonstrate that, as determined by both in vitro and in vivo assays, the Bel-1 target site located within the HFV internal promoter binds Bel-1 with a significantly higher affinity than the cap-proximal Bel-1 target site located in the LTR promoter. This result may provide a mechanistic explanation for the observation that the internal promoter is activated significantly earlier than the LTR promoter during the foamy virus life cycle.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Approach in improving potency and selectivity of kinase inhibitors: Allosteric kinase inhibitors

2020 ◽  
Vol 21 ◽  
Author(s):  
Shangfei Wei ◽  
Tianming Zhao ◽  
Jie Wang ◽  
Xin Zhai
Keyword(s):  
Protein Interactions ◽  
Kinase Inhibitors ◽  
Binding Modes ◽  
Allosteric Inhibitors ◽  
Wide Range ◽  
Allosteric Sites ◽  
Protein Functions ◽  
Regulate Protein

: Allostery is an efficient and particular regulatory mechanism to regulate protein functions. Different from conserved orthosteric sites, allosteric sites have distinctive functional mechanism to form the complex regulatory network. In drug discovery, kinase inhibitors targeting the allosteric pockets have received extensive attention for the advantages of high selectivity and low toxicity. The approval of trametinib as the first allosteric inhibitor validated that allosteric inhibitors could be used as effective therapeutic drugs for treatment of diseases. To date, a wide range of allosteric inhibitors have been identified. In this perspective, we outline different binding modes and potential advantages of allosteric inhibitors. In the meantime, the research processes of typical and novel allosteric inhibitors are described briefly in terms of structureactivity relationships, ligand-protein interactions and in vitro and in vivo activity. Additionally, challenges as well as opportunities are presented.

In vitro and in vivo characterization of graphene oxide coated porcine bone granules

Carbon ◽  
2016 ◽  
Vol 103 ◽  
pp. 291-298 ◽  
Author(s):  
Valeria Ettorre ◽  
Patrizia De Marco ◽  
Susi Zara ◽  
Vittoria Perrotti ◽  
Antonio Scarano ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
In Vivo Characterization

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

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