19 Questions
Which viral protein is responsible for directing transport of proviral DNA into the cell nucleus?
MA
What is the primary receptor found on both T lymphocytes and monocytes/macrophages?
CD4
Which viral protein causes conformational changes in viral gp120 (SU) upon binding to CD4?
Vpr
What is responsible for replicating the viral genome but generates small mutations due to absence of proofreading activity?
$RT$
Which type of viruses use CCR5 and are macrophage-tropic?
$R5$ viruses
What determines co-receptor usage in HIV-1?
Variations in viral SU (gp120)
What occurs after the close proximity of viral and host cell membranes?
Fusion domain of gp41 inserts into the host cell membrane
Which proteins are part of the preintegration complex that directs transport into the nucleus?
MA, Vpr, and IN
Which viral protein supports elongation of HIV-1 transcription by binding to TAR?
Tat
What is the role of Vpu in HIV-1 infection?
Enhancing release of progeny virions from infected cells
Which viral protein continuously shuttles between cytoplasm and nucleus?
Rev
What is the function of Vif in HIV-1 infection?
Increasing virion infectivity by counteracting host cell antiviral factors
Which HIV-1 protein can arrest infected cells in G2 stage of cell cycle?
Vpr
What is the role of Nef in HIV-1 infection?
Decreasing surface expression of CD4 and MHC1
What initiates the assembly and budding of HIV-1?
Genome packaging signal (psi) on genomic RNA
What is the consequence of Tat's absence during HIV-1 transcription?
RNA polymerase lacks processivity
Which element is sensitive to various cellular stimuli in regulating latent HIV-1 infection?
HIC-1 LTRs' transcriptional control elements
What is essential for transport of mRNAs encoding HIV-1 structural proteins?
Rev continuously shuttling between cytoplasm and nucleus
Which protein increases virion infectivity by counteracting host cell antiviral factors?
Vif
Study Notes
HIV-1 Molecular Mechanisms and Protein Functions
- HIV-1 cure is complicated by host genome integration and immune system inability to identify infected cells without viral protein expression
- Latent infection regulation involves transcriptional control elements in HIC-1 LTRs, sensitive to various cellular stimuli
- Patients with latent HIV-1 infection must continue treatment for life
- The viral Tat protein, localized in the nucleus, supports elongation of HIV-1 transcription by binding to TAR
- In absence of Tat, RNA polymerase lacks processivity, and in its presence, cellular Cdk9 and Cyclin T are recruited to enhance processivity
- Rev mediates cytoplasmic transport of viral mRNAs encoding HIV-1 structural proteins and continuously shuttles between cytoplasm and nucleus
- Tat and Rev are essential for HIV transcription and transport of mRNAs encoding structural proteins
- Vif increases virion infectivity by counteracting host cell antiviral factors such as APOBEC3G
- Vpr enhances HIV-1 replication and can arrest infected cells in G2 stage of cell cycle
- Vpu enhances release of progeny virions from infected cells and induces degradation of tetherin, a host antiviral protein
- Nef decreases surface expression of CD4 and MHC1, modifying cell signaling in T cells and affecting the immune response
- Genome packaging signal (psi) on genomic RNA initiates assembly and budding of HIV-1, with protease activation cleaving Gag and Gag-Pol polyproteins into individual peptides for infection
Test your knowledge on the structure and genome of the HIV virus, including its RNA type, packaging of cellular tRNA, and the proteins it encodes. Explore the complex components and functions of this retrovirus.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
