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slgoogin8981

HSV carrying WT REST establishes latency but reactivates only if the synthesis of REST ... - 7 views

www.pnas.org/...E498.long

shared by slgoogin8981 on 15 Oct 14 - No Cached
  • R111 recombinant is not reactivation-defective because it is able to reactivate in the presence of inhibitors of protein synthesis in the same manner as the WT parent virus, and (b) because the only significant difference in the WT and R111 viruses is the presence of the REST gene in the latter virus, the data suggest that expression of this gene blocks reactivation and that suppression of protein synthesis, including that of REST, enables reactivation.
    • becky214
      becky214 on 16 Oct 14
       
      I am confused about when REST blocks reactivation and when it enables it. It says the gene blocks reactivation but continues to say it enables it. Does REST only enable reactivation if it plays a role in suppressing protein synthesis?
  • with dexamethasone or dexamethasone and cycloheximide
  • Specifically, a stress response generated by virus entry recruits or activates REST to enable the assembly of the HCLR complex. Stress responses have been postulated to activate REST
    • becky214
      becky214 on 16 Oct 14
       
      I think this is interesting because REST is not usually found in neurons. I'm curious as to how the neuron recruits this gene. Does the virus actually recruit it? Or is it just a cellular response to the stress of viral entry? 
  • ...13 more annotations...
  • HSV takes advantage of the neuronal stress response to enter into a silent, latent state. To assist in the execution of this plan, HSV evolved a DNA sequence that allows itself to be suppressed in neurons and a mechanism to maintain an equilibrium between total suppression and potential to exit from the latent state.
  • translocated from satellite cells
  • The fundamental question is the identity of the mechanism by which a vigorously replicating virus, on entry into the body, is silenced in neurons harboring latent virus.
    • laceemarie
      laceemarie on 17 Oct 14
       
      Just to make sure that I understand this, once the virus enters the body, it quickly replicates and all the new virus particles find a nerve cell to infect and once there, the virus is able to sit in silence, so to speak?
  • Thus, VP16, a virion protein brought into the cells during infection, recruits several cellular proteins, including LSD1, to derepress α gene promoters
    • laceemarie
      laceemarie on 17 Oct 14
       
      VP16, a virion protein and a recruiter - this protein sounds pretty important to me. Is there a way or has there been work done with this protein to not allow the derepression at this checkpoint? Is it possible to keep a virus in latency because of alpha gene promoters not getting derepressed so as to not allow the virus to infect the host? I'm not sure if that's a reasonable antiviral therapy or not.
  • In some neurons, the virus establishes a latent, silent state. In other neurons, the virus replicates, and it is most likely that the virus in these neurons is transmitted and replicates in other ganglionic cells.
    • laceemarie
      laceemarie on 17 Oct 14
       
      Is this a random event or does this have something to do with the environment of the neuron? I would assume that specific, different environments would be ideal for each.
  • Finally, in contrast to the events following entry of virus after retrograde transport from the periphery, the data suggest that reactivation does not trigger a stress response that leads to activation of REST
    • alexridesducati
      alexridesducati on 17 Oct 14
       
      Has anyone been able to pinpoint the exact step in infection that activates REST so that it can be studied? If so, perhaps it is possible to manipulate the effects of that step in order to induce an artificial response to the reactivation of HSV1 from its latency period in order to retrigger the stress response that leads to REST activation.
  • Thus, VP16, a virion protein brought into the cells during infection, recruits several cellular proteins, including LSD1, to derepress α gene promoters. One α gene product, infected cell protein 0 (ICP0), derepresses β and γ1 genes. Ultimately, the onset of viral DNA synthesis enables the expression of very late, or γ2, genes (4).
    • Sean Hogan
      Sean Hogan on 17 Oct 14
       
      Is this why the latent infection occurs in the ganglia of the PNS? The necessary proteins for gene derepression can't be recruited in the CNS or other cells?
  • In contrast, simultaneous expression of all viral genes during reactivation from latency is likely to minimize yield, but the mission of the virus is to assemble enough viruses to reach the portal of egress from the body (e.g., mouth, genitals) rather than to overwhelm the host with infectious virus.
    • Sean Hogan
      Sean Hogan on 17 Oct 14
       
      This might be the coolest statement in the whole paper. The discussion above kind of painted a picture of HSV infecting the PNS only but the reason for it's inability to reach the CNS didn't receive as much attention. I think this statement summed it all up though.HSV doesn't care about high virion yields or whether a productive or latent infection is necessary, it just wants to reach the body portals. The virus is "smart," enough to avoid the CNS and keep it's host alive.
  • Between 5 and 24 h after excision, mRNAs representative of all viral gene kinetic groups increase 100-fold in amount. Viral DNA also increases in amount, indicating that viral proteins are made. At the same time, viral LAT and miRNA concentrations decrease at least 10-fold (34). It is convenient to define the initial phase lasting no more than 5 h as the preactivation phase and the remaining time interval as the activation phase.
    • rmeloche10
      rmeloche10 on 17 Oct 14
       
      I'm having trouble grasping why the massive disparity between viral DNA and viral LAT. Obviously there would be some disparity when reactivation occurs, but wouldn't the production of more DNA contribute to even a small amount of LAT production and not a minimal 10 fold decrease?
  • The same concentration of HDAC inhibitor was ineffective in inducing the reactivation of R111 recombinant virus in ganglionic organ cultures maintained in medium containing anti-NGF antibody.
    • ameliaobert
      ameliaobert on 18 Oct 14
       
      Interesting: That there is an inhibitor for chromatin remodelling (HDAC). Confusing: Is if HDAC can inhibit properly for WT virus, but not for R111 recombinant, that obtains REST. How does REST make the HDAC inhibitor ineffective ia stressed neuron? I understand that REST is what the DNA can be wrapped about and help with latency, so it that why the HDAC cannot inhibit, since REST is already aiding in latency.
    • nleonard11
      nleonard11 on 20 Oct 14
       
      I thought this process of finding out that the HCLR complex activates from stress was very interesting. Using WT viral genomes appears to be a very effective way to test many virus functions.
    • nleonard11
      nleonard11 on 20 Oct 14
       
      I was just wondering why the virus goes into a latent after 30 days? What exactly is it waiting to do and what conditions need to be present for it to become active again.
    • slgoogin8981
      slgoogin8981 on 19 Nov 14
       
      It would be interesting to know the amount that REST is seen in non-neural cells and nerve cells in the absents of HSV-1. I was state earlier that REST is not normally found in never cells.
Casey Finnerty

The Quest to End the Flu - Carl Zimmer - The Atlantic - 0 views

www.theatlantic.com/...354677

influenza virology vaccination

shared by Casey Finnerty on 21 Nov 13 - No Cached
  • Fauci is more excited about something called a recombinant protein vaccine, which does not rely on growing viruses, even though it is cell-based. At Protein Sciences, a small Connecticut biotech firm, researchers isolate the gene for the flu virus’s surface proteins and insert it into an entirely different species of virus, called a baculovirus. The baculovirus infects insect cells and causes them to make huge amounts of the surface proteins, which the company uses to make Flublok, the only recombinant protein flu vaccine currently available.
  • The researchers have tried various methods, including the same one used to make Flublok—insect cells churning out surface proteins.
  • “The eggs should be long gone,” grumbles Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
  • ...1 more annotation...
  • Manufacturers for the most part still make flu vaccines the way they did in World War II: in chicken eggs.
Sarah Muncy

ScienceDirect.com - Vaccine - Intranasal and intramuscular immunization with Baculoviru... - 0 views

www.sciencedirect.com/...S0264410X10009412

shared by Sarah Muncy on 27 Sep 12 - No Cached
  • An anti-malarial transmission-blocking vaccine (TBV) that prevents fertilization and/or ookinete/oocyst development within the mosquito is an attractive strategy to limit the transmission of malaria
  • The present study used this system to generate a Plasmodium vivax transmission-blocking immunogen (AcNPV-Dual-Pvs25).
  • Plasmodium vivax
  • ...10 more annotations...
  • A variety of expression vectors (e.g., Escherichia coli, Pichia pastoris and DNA) have been used to express Pvs25 protein which has been administered alone or in combination with adjuvants
  • To date these studies suggest that the recombinant protein currently requires both not only linear, but conformation dependent epitopes, and a strong adjuvant to induce transmission-blocking antibodies.
  • Intranasal and intramuscular immunization with Baculovirus Dual Expression System-based Pvs25 vaccine substantially blocks Plasmodium vivax transmission
  • Recently, we have developed a new vaccine vector system based on the baculovirus Autographa californica nucleopolyhedrosis virus (AcNPV) termed the “Baculovirus Dual Expression System”, which drives expression of vaccine candidate antigens by a dual promoter that consists of tandemly arranged baculovirus-derived polyhedrin and mammalian-derived CMV promoters. It has been shown that AcNPV, an enveloped double-stranded DNA virus that naturally infects insects, possesses strong adjuvant properties that can activate dendritic cell-mediated innate immunity
  • Mucosal vaccines have several attractive features compared with parenteral vaccines (e.g., safety, cost-effectiveness and ease of administration), but studies on their use have been limited almost exclusively to protection against mucosally transmitted pathogens. We provide evidence that i.n. immunization is a feasible alternative for preventing malaria, which is transmitted through non-mucosal routes
  • These results are consistent with our previous work showing that intranasal immunization with the baculovirus-based vaccine induced strong systemic humoral immune responses with high titres of antigen-specific antibodies and conferred complete protection against malaria blood-stage challenge
  • which can induce immunological memory against heterologous antigens in a rodent model; however, it is precluded from clinical use due to its enterotoxicity and potential hazardous effects on olfactory nerves [22]. In contrast, a baculovirus-based delivery system may offer an attractive immunization method, as AcNPV exhibits low cytotoxicity and is incapable of replication in mammalian cells
  • The data described here adds to previously presented data showing the significant potential of the baculovirus dual expression system against the blood stages of the parasite
  • but also demonstrates clearly its ability to induce antibodies against the ookinete surface protein Pvs25, and to elicit a transmission-blocking immune response against the P. vivax isolates from endemic areas, and a transgenic rodent malaria parasite model in preliminary studies.
  • One was SMFA on peripheral blood from P. vivax infected patients.
  • Sarah Muncy on 27 Sep 12
     
    Reference paper #2. Gave me information on malaria and baculoviruses.
Casey Finnerty

Production of swine flu vaccine is way behind - Yahoo! News - 2 views

news.yahoo.com/...us_med_swine_flu_chicken___egg

vaccine virology

shared by Casey Finnerty on 29 Aug 12 - Cached
  • Also, Protein Sciences Corp. of Meriden, Conn., landed a five-year, $147 million contract to develop a vaccine using its recombinant technology — flu proteins grown in insect cells. The hope is that the first doses would be available within 12 weeks of the beginning of a pandemic. That is about twice as fast as flu vaccine produced from eggs.
Casey Finnerty

Recovery of genetically defined murine norovirus in tissue culture by using a fowlpox v... - 1 views

vir.sgmjournals.org/...2091.full

norovirus

shared by Casey Finnerty on 22 Sep 14 - No Cached
  • Previous calicivirus reverse-genetics systems have relied on the transfection of either in vitro-transcribed, 5′-capped calicivirus genomic RNA (Chang et al., 2005; Sosnovtsev & Green, 1995) or cDNA constructs, followed by delivery of T7 RNA polymerase using a VACV recombinant (Sosnovtsev et al., 2002; Thumfart & Meyers, 2002). A recent report on rabbit hemorrhagic disease virus (RHDV) has also demonstrated that in vitro-transcribed, uncapped RNA is infectious when transfected into cells or delivered directly to the liver in vivo (Liu et al., 2006). Attempts to recover MNV by using any of these established approaches failed to produce infectious virus (data not shown).
  • Casey Finnerty on 22 Sep 14
     
    This paper contains very good background on the development of the MNV reverse genetics system. The norovirus genome is uncappped, but transfection with uncapped mRNAs does NOT produce many progeny virions.
apopp10

Norovirus Translation Requires an Interaction between the C Terminus of the Genome-link... - 75 views

www.jbc.org/...21738.long

shared by apopp10 on 12 Sep 14 - No Cached
  • Importantly, however, despite the interaction between the norovirus VPg protein and eIF4E, it appears to be dispensable for MNV translation initiation, at least in vitro
    • ameliaobert
      ameliaobert on 15 Sep 14
       
      I find it interesting that the MNV is depensable if incorporated in vitro. Im curious as to why this could be.
    • Casey Finnerty
      Casey Finnerty on 26 Sep 14
       
      They are saying the VPg-eIF4E interaction is dispensable in vitro, not the virus itself.
  • Mass spectrometry was used to identify proteins present within the samples with a minimum of 2 unique peptides and >90% identification probability
    • laceemarie
      laceemarie on 16 Sep 14
       
      I'm confused as to how exactly mass spectrometry was used in this experiment. If the proteins are already separated by molecular weight after the SDS-PAGE, what precisely are they looking for when running a mass spec? It article says, ".... a minimum of 2 unique peptides and >90% identification probability," but this doesn't mean much to me. I understand the identification part because based on the way the molecule splits after being shot with ions, you can get a basic idea of the structure of the molecule. My question with the 2 unique peptides is that each amino acid has a different molecular weight right? So if the proteins were all the same except at the 2 unique peptides, the mass spec would show a different mass to charge ratio for each protein with the varying peptides correct? Would the charge of the amino acids in the peptide have anything to do with the charge portion of the mass to charge ratio? I hope this question came out okay. 
    • abachman12
      abachman12 on 22 Sep 14
       
      I also found this confusing. I understand what your saying and it makes your question makes sense to me. I think that the charge of the amino acids in the peptide would have something to do with the charge portion of the mass to charge ration.
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      I'll address this in class. In the meantime, check out http://en.wikipedia.org/wiki/Peptide_mass_fingerprinting
  • inability to culture many members of the virus family in immortalized cells.
    • slgoogin8981
      slgoogin8981 on 17 Sep 14
       
      What are the other options to culture these viruses?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      This is the subject of intense study. See ref 18.
  • ...34 more annotations...
  • The mutation F123A ablated the ability of VPg to co-purify eIF4G, eIF4A, and PABP but did not affect the ability of NTAP-MNV VPg to co-purify eIF4E (Fig. 5), suggesting that the eIF4E and eIF4G binding regions on VPg are distinct
    • ameliaobert
      ameliaobert on 17 Sep 14
       
      If F123A mutation is observed through data analysis (co-purification) that the eIF4E and eIF4G are distinct, so differ from each other. Then, why does the data suggest that the direct interacts of VPg with eIF4G determines the eIF4F binding capacity from the data obtained? As well as how do these purification datas are able to determine if the binding capacities for the virus VPg proteins are direct interactions?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      As written, your question is unclear. Please rewrite it.
  • These data would suggest that the direct interaction of VPg with eIF4G largely determines the eIF4F binding capacity of the norovirus VPg protein.
  • some of which function directly in translation initiation, whereas others may contribute to the regulation of host cell translation by virus infection.
    • ameliaobert
      ameliaobert on 17 Sep 14
       
      So here, they are saying that the initiation factors, some directly interact with the viruses translation to mRNA, whereas the other initiation factors present in teh virus contribute there translation factors specifically to when the host cells get involved with the virus translation factors? Basically specifically encoding for specific initiation translation factors based on the area of translation (i.e. from the virus or from the host cell)?
  • using the number of unique peptides identified for each protein (Table 1) as a semiquantitative indirect measure of protein abundance in the purified complex, it was also apparent that eIF4G was enriched in the complex with respect to the other proteins isolated.
    • becky214
      becky214 on 18 Sep 14
       
      I was confused by what they are suggesting with this data. Is it true that elF4G is a binding partner, or is it just suggested?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      Suggested. What evidence do you think would be conclusive?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      BTW, is that a golden eagle in your picture?
  • we attempted
  • to identify
  • components of the complex that interacted with VPg directly and contribute to viral translation
    • slgoogin8981
      slgoogin8981 on 18 Sep 14
       
      Is this the same as saying, they were looking for promoters?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      No. Promoters are involved with transcription. In this paper they are looking for eIF's (of translation) that interact with VPg.
  • Independent observations indicate that eIF4G phosphorylation is stimulated during norovirus replication in cell culture and that this phosphorylated form of eIF4G is associated with MNV VPg in infected cells (29). The impact and functional relevance of initiation factor phosphorylation on the norovirus life cycle is currently under study.
    • becky214
      becky214 on 19 Sep 14
       
      Maybe it is possible that this phosphorylation helps initiate and enhance translation.
    • alexridesducati
      alexridesducati on 19 Sep 14
       
      It seems in order for this virus to replicate effectively, it has to bind several different ways, at least, just to initiate protein synthesis. Is there any way to synthesize a molecule that can target any of these proteins for degradation or at least something that can inhibit the binding site (similar to a neutralizing antibody :) . It seems that if you nip this right at the bud, that its possible to shut this virus down for the most part, except for the fact that in vitro, elF4E can be dispensed for translation initiation. Makes me wonder what the key differences are between an in vitro and in vivo environment that allows this to happen.
  • high affinity interaction
    • smolizon11
      smolizon11 on 19 Sep 14
       
      Im confused to as what high affinity means?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      High affinity would mean a tighter interaction between two molecules. The high affinity nature of the VPg-eIF4G interaction is suggested by the fact that eIF4G is carried through the TAP procedure, and that it persists despite washing with 1M salt.
  • Noroviruses, members of the Caliciviridae family of small positive-strand RNA viruses, are a major cause of acute gastroenteritis
    • smolizon11
      smolizon11 on 19 Sep 14
       
      Its really interesting to be able to put a virus with being the cause of certain diseases. Even when talking about the disease in a "non-medical" setting its almost as if you have "higher hand" at the information about it. Makes for fun and interesting conversation with other people besides virology students.
  • As these proteins were not identified in both experimental systems and the focus of this study was to determine the role of canonical initiation factors in VPg-dependent translation, these additional host cell proteins factors were not examined in more detail.
    • Sean Hogan
      Sean Hogan on 19 Sep 14
       
          Is it possible that any of these are binding far upstream or downstream from the IF complex yet still affect affinity of complex compoenets such as with the eIF4E interaction with VPg protein in vitro?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      Yes.
  • recombinant MNV was performed by infecting baby hamster kidney cells with fowlpox virus expressing T7 RNA polymerase followed by transfection of MNV cDNA expression constructs as described previously
    • slgoogin8981
      slgoogin8981 on 19 Sep 14
       
      Was the fowlpox used just for the purpose of its polymerase? What is cDNA?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      cDNA stands for complementary DNA. Technically, that would mean the DNA strand that is complementary in sequence to the RNA. In practice, after the first cDNA strand is synthesized (typically using an RNA template and reverse transcriptase), the second strand is synthesized with a DNA polymerase as well. This double-stranded cDNA can then be cloned in a plasmid, which is then introduced into cells via transfection as done by the Goodfellow group. The fowlpox encoding RNA polymerase from T7 phage (this RNA pol is not error prone and highly specific for the T7 transcription start site) is used for two things: the T7 RNA polymerase drives transcription of the MNV RNA from the plasmid containing the cDNA; AND it also promotes capping of the MNV genome/transcript, which promotes translation of MNV proteins. See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3471295/, Fig. 4.
    • slgoogin8981
      slgoogin8981 on 26 Sep 14
       
      Thank you for the link! I am very unskilled with the lab results and procedures done in lab. I appreciate the guidance and opportunity to learn. I have only had three biology labs: 241, 242 and Cell.
    • Casey Finnerty
      Casey Finnerty on 01 Oct 14
       
      You're welcome! And thanks for the question!
  • human noroviruses have yet to be cultivated in the laboratory (18).
  • Our understanding of norovirus biology has been greatly enhanced by the discovery of murine norovirus (MNV) in 2003 (19),
  • Previous reports have also highlighted a potential association of the norovirus VPg protein with components of the eIF3 complex (28) and eIF4E, PABP, and eIF4G as well as the ribosomal protein S6 (29), although the functional relevance of these interactions has yet to be demonstrated. Here we describe the proteomic characterization of the murine norovirus translation initiation factor complex, demonstrating that VPg associates directly with the core components of the eIF4F complex and PABP. We further demonstrate that the interaction between eIF4G and VPg is essential for norovirus translation. Furthermore, we demonstrate that eIF4G is required for efficient virus replication in cell culture.
  • although these cells are not permissive to MNV infection due to the lack of a suitable receptor, robust MNV translation and replication occurs upon transfection of viral RNA into the cytoplasm (22).
    • slgoogin8981
      slgoogin8981 on 19 Sep 14
       
      It is very cool that this virus can still use human translation equipment even though it is a marine from of the virus. How did they enter the virus genome into the cytoplasm?
  • It is worth noting, however, that in addition to disrupting electrostatic interactions, increasing sodium chloride concentrations stabilize hydrophobic interactions.
  • It is important to note that in both these approaches low levels of eIF4E remained (Fig. 8C) and 4E-BP1 expression in the MNV permissive cells did not completely block the eIF4E-4G interaction. Therefore, further studies on the role of eIF4E during the norovirus life cycle are clearly warranted, but it is worth noting that in addition to a direct role in cap binding for translation initiation, eIF4E plays numerous roles in the regulation of gene expression.
    • jpolanco10
      jpolanco10 on 19 Sep 14
       
      Why did this not block the eIF4E-4G interaction? Is there a really high affinity or was it able to recruit other proteins to aide it? It seems that the low level of eIF4E was still able to do its job, mainly regulation of the genes
  • Murine macrophage RAW264.7 and microglial BV2 cell lines were cultured in Dulbecco's modified Eagle's medium (DMEM) with 10% (v/v) fetal calf serum (FCS), penicillin (100 units/ml), streptomycin (100 μg/ml), and 10 mm HEPES buffer. Baby hamster kidney cells (BHK-21) expressing T7 RNA polymerase (BSRT7 cells) were cultured in similar media lacking HEPES but containing 1 mg/ml G418. Similarly, HEK 293T cells were maintained in media lacking HEPES. HEK 293T cells stably expressing pMEP4-NTAP or pMEP4-NTAP MNV VPg plasmids were supplemented with 50 μg/ml hygromycin B and nonessential amino acids. The HEK293 TREX cells stably expressing pcDNA4/TO-NTAP derivatives of MNV VPg were supplemented with 5 μg/ml Blasticidin and 200 μg/ml Zeocin. All cell lines were maintained at 37 °C and 10% CO2.
    • nkasdagly
      nkasdagly on 19 Sep 14
       
      Are they setting up the primary and secondary antibodies here or am i totally off? Just wondering because i see they used fetal calf serum and baby hampster kidney cells... 
  • Noroviruses, members of the Caliciviridae family of small positive-strand RNA viruses, are a major cause of acute gastroenteritis in man (8) but have also been identified in a number of other species including dogs (9, 10), cats (11), sheep (12), and cattle (13
    • Sean Hogan
      Sean Hogan on 19 Sep 14
       
      Work?
  • the first step in translation is the binding of the initiation factor eIF4E, a component of the eIF4F complex, to the 5′ cap structure.
  • eIF4F is a complex of three initiation factors; eIF4E is the cap-binding protein, eIF4A functions as an RNA helicase, and eIF4G acts as a scaffold to bridge the mRNA to the 40 S ribosomal subunit via its interaction with eIF3 (3).
  • 14 individual point mutations in VPg were introduced into the MNV infectious clone,
  • the effect of mutations on the ability of VPg to associate with initiation factors was assessed by the enrichment of the eIF4F complex using m7GTP-Sepharose followed by Western blotting for VPg.
  • the mutations V115A, D116A, and F123A altered the levels of infectious virus produced;
  • the mutants V115A, D116A, and F123A showed a consistently reduced interaction with eIF4F (Fig. 4).
  • The degree to which the mutation affected virus recovery appeared to correlate with the ability of VPg to be co-purified with initiation factors (Fig. 4).
  • These data would indicate that the disordered C terminus of the norovirus VPg protein contains amino acids involved in the interaction with eIF4G.
  • We recently analyzed the solution structure of the core domain of VPg using nuclear magnetic resonance (NMR) spectroscopy and found that the MNV VPg protein consists of a compact structured core formed by a pair of α-helices that is flanked by long, flexible N and C termini (35). The region we have identified as being involved in the direct interaction with eIF4G, namely the C-terminal domain, is disordered and, therefore, is likely to adopt a fixed structure only upon interaction with eIF4G.
    • rmeloche10
      rmeloche10 on 22 Sep 14
       
      Using this advanced spectroscopy to find the structured core is an awesome break in technology. It shows the C-terminal is disordered until interaction with the initiation factor, does this disorder provide any advantage within the virus?
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
  • eIF4GI
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      eIF4GI and eIF4GII are related forms of eIF4G.
  • This approach was used in place of authentic infection to enable the use of the F123A VPg mutant as a specificity control as this cDNA clone does not produce infectious virus (Fig. 4).
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      Throughout the paper, the authors have included helpful explanatory text like this.
  • These data indicate that the VPg binding site lies within residues 654–1131 of eIF4GI, a region known to contain both eIF4A and eIF3 binding sites (7).
    • Casey Finnerty
      Casey Finnerty on 22 Sep 14
       
      Couldn't the binding site be narrowed further to 675-1131?
  • Noroviruses, a major cause of gastroenteritis in man, have evolved a mechanism that relies on the interaction of translation initiation factors with the virus-encoded VPg protein covalently linked to the 5′ end of the viral RNA.
    • apopp10
      apopp10 on 08 Dec 14
       
      I guess this comment never got adhered to my original highlight. Here it is once more. As someone who has gastrointestinal issues including inflammation, i wonder if this virus could have played a role in the cause of my condition, Ulcerative Colitis. I think interrupting this interaction could provide an effective treatment against this virus.
  • Casey Finnerty on 12 Sep 14
     
    Journal Article for our Week 4 discussion.
becky214

Targeting therapeutics to an exposed and conserved binding element of the HIV-1 fusion ... - 10 views

www.ncbi.nlm.nih.gov/...PMC154290

shared by becky214 on 18 Nov 14 - No Cached
  • We report that the C-terminal region of the HIV-1 gp41 ectodomain (and gp160 precursor molecule) appears to be partially exposed and vulnerable to an antiviral agent before the receptor-mediated conformational changes that initiate membrane fusion.
    • laceemarie
      laceemarie on 18 Nov 14
       
      How long is this domain "exposed and vulnerable" before the membranes fuse? Would whatever antiviral treatment that targets this have to be able to hang around, so to speak, for a while in between HIV-host interactions, without being degraded or absorbed or moved to another place in or out of the body?
  • and those that can eliminate infected cells, thereby reducing persistent and latent reservoirs of the virus.
    • apopp10
      apopp10 on 30 Nov 14
       
      It would be interesting to see if there will be a drug that can eventually do this that will be low-cost and is manageable in dosage. The problem is how much the virus mutates to evade these drugs and the host immune system. Combination therapy with the RT inhibitor, protease inhibitor, the experimental design listed her and this drug may be effective at treating HIV in the future.
  • These studies do not determine whether 5-Helix interacts with the native conformation of Env or, rather, some misfolded conformation of gp41 and gp160 on the cell surface.
    • Sean Hogan
      Sean Hogan on 02 Dec 14
       
      What would cause the misfolding of Env? Wouldn't it be advantageous to interact with both in order to prevent HIV infection?
  • ...2 more annotations...
  • Moreover, we demonstrate that this binding is sufficient to concentrate a recombinant toxin to selectively kill HIV-1-infected cells. Our results suggest that the gp41 C-peptide region is a viable target for development of antiviral therapeutics, neutralizing antibodies, and cytotoxic agents directed against infected cells.
    • becky214
      becky214 on 06 Dec 14
       
      How could this help develop antibodies when it is a a toxin that will kill HIV-1-infected cells? 
  • Such a molecule, administered together with agents that induce the expression of dormant integrated provirus (e.g., cytokines or activators of protein kinase C), might help to reduce or possibly eliminate latent reservoirs of HIV-1
    • becky214
      becky214 on 06 Dec 14
       
      I think this is really interesting that it can possibly eliminate HIV that is latent. I have not heard of any anti-viral agents that target latent cells, and this sounds like it could be revolutionary in research on HIV-1.
  • alexridesducati on 18 Nov 14
     
    Focus paper for wednesday
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