HIV Virus Structure and Genome

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Questions and Answers

Which viral protein is responsible for directing transport of proviral DNA into the cell nucleus?

MA (correct)

Vif

What is the primary receptor found on both T lymphocytes and monocytes/macrophages?

Vpu

CD4 (correct)

CCR5

CXCR4

Which viral protein causes conformational changes in viral gp120 (SU) upon binding to CD4?

Vpr (correct)

What is responsible for replicating the viral genome but generates small mutations due to absence of proofreading activity?

$RT$ Signup and view all the answers

Which type of viruses use CCR5 and are macrophage-tropic?

$R5$ viruses Signup and view all the answers

What determines co-receptor usage in HIV-1?

Variations in viral SU (gp120) Signup and view all the answers

What occurs after the close proximity of viral and host cell membranes?

Fusion domain of gp41 inserts into the host cell membrane Signup and view all the answers

Which proteins are part of the preintegration complex that directs transport into the nucleus?

MA, Vpr, and IN Signup and view all the answers

Which viral protein supports elongation of HIV-1 transcription by binding to TAR?

Tat Signup and view all the answers

What is the role of Vpu in HIV-1 infection?

Enhancing release of progeny virions from infected cells Signup and view all the answers

Which viral protein continuously shuttles between cytoplasm and nucleus?

Rev Signup and view all the answers

What is the function of Vif in HIV-1 infection?

Increasing virion infectivity by counteracting host cell antiviral factors Signup and view all the answers

Which HIV-1 protein can arrest infected cells in G2 stage of cell cycle?

Vpr Signup and view all the answers

What is the role of Nef in HIV-1 infection?

Decreasing surface expression of CD4 and MHC1 Signup and view all the answers

What initiates the assembly and budding of HIV-1?

Genome packaging signal (psi) on genomic RNA Signup and view all the answers

What is the consequence of Tat's absence during HIV-1 transcription?

RNA polymerase lacks processivity Signup and view all the answers

Which element is sensitive to various cellular stimuli in regulating latent HIV-1 infection?

HIC-1 LTRs' transcriptional control elements Signup and view all the answers

What is essential for transport of mRNAs encoding HIV-1 structural proteins?

Rev continuously shuttling between cytoplasm and nucleus Signup and view all the answers

Which protein increases virion infectivity by counteracting host cell antiviral factors?

Vif Signup and view all the answers

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

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Description

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.