Coronavirus Virion Structure
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Questions and Answers

What type of proteins are generally involved in mediating membrane fusion?

  • Type I transmembrane proteins (correct)
  • Type II transmembrane proteins
  • Glycosylphosphatidylinositol (GPI)-anchored proteins
  • Peripheral membrane proteins
  • How is energy involved in the fusion process mediated by viral fusion proteins?

  • Metabolic energy is required for the conformation changes leading to fusion
  • Energy is not involved in the viral fusion process
  • Conformation changes lead to the presence of energy, and fusion occurs without the need for ATP/metabolic energy (correct)
  • ATP is directly utilized in the fusion process
  • What role do fusion proteins play in viral infection?

  • They play a critical role in viral infection and can be therapeutic targets (correct)
  • They are only involved in viral entry but not in the infection process
  • They have minimal impact on viral infection
  • They are not essential for viral infection
  • What are the characteristics of Class II fusion proteins?

    <p>Mostly beta-sheets, tend to form dimers, and involve rearrangement of multimers of protein subunits with minor conformational changes at tertiary level</p> Signup and view all the answers

    Which part of the nascent RNA chain forms RNA-RNA hybrids at 5’ TRS?

    <p>End of the leader sequence</p> Signup and view all the answers

    What can lead to template switch if polymerase fails to find another template after dissociation?

    <p>Recombination between viral genomes</p> Signup and view all the answers

    Where does the assembly of virions take place?

    <p>Endoplasmic reticulum Golgi intermediate compartment (ERGIC)</p> Signup and view all the answers

    Which proteins play important roles in the formation of virus envelopes by budding?

    <p>M and E proteins</p> Signup and view all the answers

    What interacts with packaging signals in N to ensure only full-length viral RNA gets packaged into virions?

    <p>$3’$ end of the cytoplasmic tail of M protein</p> Signup and view all the answers

    Where are mature virions packaged before being transported to the cell surface for release?

    <p>Golgi membrane</p> Signup and view all the answers

    What is responsible for incorporating HE (if present) and S into the membrane?

    <p>M protein</p> Signup and view all the answers

    What plays a crucial role in mediating transport, processing, and modification of proteins in ERGIC?

    <p>M protein</p> Signup and view all the answers

    What may help with genome repair and/or generate new viral strains/variants?

    <p>Recombination between viral genomes due to template switching</p> Signup and view all the answers

    Which protein is responsible for viral entry and tropism, and is targeted by neutralizing antibodies and T-cells in infection?

    <p>Spike protein</p> Signup and view all the answers

    What is the composition of the replicase gene (gene 1)?

    <p>ORF1a and ORF1b partially overlapping reading frames</p> Signup and view all the answers

    Which cellular receptors do spike proteins bind to?

    <p>Aminopeptidase-N, sialic acid, ACE2, L-SIGN, TMPRSS2</p> Signup and view all the answers

    What is the common membrane association for viral RNA synthesis among '+' strand RNA viruses of eukaryotes?

    <p>Membrane association of viral RNA synthesis</p> Signup and view all the answers

    What is the structure of coronavirus nucleocapsids?

    <p>Formed from viral N-protein bound to viral RNA in a helical fashion</p> Signup and view all the answers

    What is the role of the M-protein in some coronaviruses?

    <p>Forming a spherical core structure containing an internal helical nucleocapsid</p> Signup and view all the answers

    What are the components of corona virions' envelope proteins?

    <p>Spike (S), membrane (M), envelope (E), nucleocapsid (N), and in some cases HE (hemagglutinin esterase) protein</p> Signup and view all the answers

    What happens after fusion mediated by spike proteins?

    <p>Viral proteins are synthesized that organize and catalyze viral RNA synthesis</p> Signup and view all the answers

    Where are replication complexes commonly observed for coronaviruses?

    <p>On double membrane vesicles by EM</p> Signup and view all the answers

    How does genome replication proceed for coronaviruses?

    <p>Via a full-length negative-strand intermediate, and subgenomic mRNAs are transcribed from subgenomic negative strand mRNA templates</p> Signup and view all the answers

    What assists with replication and packaging of the viral genome in coronaviruses?

    <p>RNA helicase and nucleoside triphosphatase</p> Signup and view all the answers

    How do non-enveloped viruses penetrate host membranes?

    <p>By utilizing cellular transport systems</p> Signup and view all the answers

    Where do many DNA viruses use for replication and latency establishment?

    <p>Nucleus</p> Signup and view all the answers

    What is a target for antiviral drugs in virus replication cycle?

    <p>Every step in the virus replication cycle</p> Signup and view all the answers

    How can viruses enter the nucleus?

    <p>During mitosis</p> Signup and view all the answers

    What are some ways to prevent virus entry into host cells?

    <p>Neutralizing antibodies and receptor occupation</p> Signup and view all the answers

    What is targeted by antiviral strategies during virus internalization?

    <p>Cellular processes for internalization</p> Signup and view all the answers

    What process do antiviral strategies target related to membrane fusion?

    <p>Membrane fusion</p> Signup and view all the answers

    What are the advantages of narrow spectrum antivirals?

    <p>Reduced likelihood of resistance development</p> Signup and view all the answers

    What are the disadvantages of broad spectrum antivirals?

    <p>Increased risk of side effects</p> Signup and view all the answers

    What is a characteristic of coronaviruses regarding their structure?

    <p>Enveloped with helical capsid</p> Signup and view all the answers

    What is a key feature of SARS and COVID-19?

    <p>Airborne transmission</p> Signup and view all the answers

    Study Notes

    Virus Replication and Antiviral Strategies

    • Non-enveloped viruses penetrate host membranes without lysis or rupture
    • Viruses utilize cellular transport systems for efficient transport to the cytosol
    • Many DNA viruses use the nucleus for replication and can establish latency
    • Strategies for viruses to pass through the nuclear membrane
    • Various ways for viruses to enter the nucleus, including during mitosis
    • Every step in the virus replication cycle is a target for antiviral drugs
    • Different ways to prevent virus entry, including neutralizing antibodies and receptor occupation
    • Specific inhibitors and agents used to interfere with cellular processes for internalization
    • Antiviral strategies targeting membrane fusion and uncoating of capsids
    • Advantages and disadvantages of narrow and broad spectrum antivirals
    • Characteristics of coronaviruses, including structure and genome
    • Overview of the history, impact, and characteristics of SARS and COVID-19

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