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The Life-Cycle of the HIV-1 Gag – RNA Complex

View Article: PubMed Central - PubMed

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) replication is a highly regulated process requiring the recruitment of viral and cellular components to the plasma membrane for assembly into infectious particles. This review highlights the recent process of understanding the selection of the genomic RNA (gRNA) by the viral Pr55Gag precursor polyprotein, and the processes leading to its incorporation into viral particles.

No MeSH data available.


The late phase of retroviral cycle highlighting the dimerization event and the Gag–RNA complex formation. Full-length genomic RNA (gRNA) as well as singly and multi-spliced viral RNAs are produced by the host cell machinery and exported into the cytoplasm. Two copies of genomic RNA (gRNA) are encapsidated inside the newly synthesized viral particle as a dimer. The interaction of Gag with the gRNA in the cytoplasm ensures its specific encapsidation. Targeting of the Gag–RNA complex to the plasma membrane (PM) is promoted by host transfer RNA (tRNA) binding to the Gag matrix (MA) domain. Since the spatio-temporal parameters of these related events remain unclear, this figure depicts the different possibilities. CA: capsid; NC: nucleocapsid; RT: reverse transcriptase; PR: protease; IN: integrase; CRM1: Chromosomal Maintenance 1; LTR: long terminal repeat.
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viruses-08-00248-f001: The late phase of retroviral cycle highlighting the dimerization event and the Gag–RNA complex formation. Full-length genomic RNA (gRNA) as well as singly and multi-spliced viral RNAs are produced by the host cell machinery and exported into the cytoplasm. Two copies of genomic RNA (gRNA) are encapsidated inside the newly synthesized viral particle as a dimer. The interaction of Gag with the gRNA in the cytoplasm ensures its specific encapsidation. Targeting of the Gag–RNA complex to the plasma membrane (PM) is promoted by host transfer RNA (tRNA) binding to the Gag matrix (MA) domain. Since the spatio-temporal parameters of these related events remain unclear, this figure depicts the different possibilities. CA: capsid; NC: nucleocapsid; RT: reverse transcriptase; PR: protease; IN: integrase; CRM1: Chromosomal Maintenance 1; LTR: long terminal repeat.

Mentions: In order to generate an infectious particle, HIV-1 must selectively package two copies of its unspliced positive sense and single-stranded gRNA [8,9]. Genome encapsidation is highly specific, allowing the gRNA to be efficiently selected from a much larger pool of cellular and subgenomic viral RNA species (reviewed in [10,11]). This specificity is achieved through the recognition of cis-acting packaging signals by the Gag precursor protein which are also thought to be regulated by RNA conformational switches [12,13,14,15,16]. The major packaging signal comprises the 5′ untranslated region (UTR), the beginning of the Gag coding sequence [17,18,19,20,21,22,23], and may include other regions within the gRNA [24,25,26]. The gRNA is initially selected in the cytoplasm by a limited number of Gag molecules. The Gag–RNA complex then nucleates viral assembly at the plasma membrane. However, the spatio-temporal parameters of gRNA recognition and viral assembly remain incomplete (Figure 1).


The Life-Cycle of the HIV-1 Gag – RNA Complex
The late phase of retroviral cycle highlighting the dimerization event and the Gag–RNA complex formation. Full-length genomic RNA (gRNA) as well as singly and multi-spliced viral RNAs are produced by the host cell machinery and exported into the cytoplasm. Two copies of genomic RNA (gRNA) are encapsidated inside the newly synthesized viral particle as a dimer. The interaction of Gag with the gRNA in the cytoplasm ensures its specific encapsidation. Targeting of the Gag–RNA complex to the plasma membrane (PM) is promoted by host transfer RNA (tRNA) binding to the Gag matrix (MA) domain. Since the spatio-temporal parameters of these related events remain unclear, this figure depicts the different possibilities. CA: capsid; NC: nucleocapsid; RT: reverse transcriptase; PR: protease; IN: integrase; CRM1: Chromosomal Maintenance 1; LTR: long terminal repeat.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5035962&req=5

viruses-08-00248-f001: The late phase of retroviral cycle highlighting the dimerization event and the Gag–RNA complex formation. Full-length genomic RNA (gRNA) as well as singly and multi-spliced viral RNAs are produced by the host cell machinery and exported into the cytoplasm. Two copies of genomic RNA (gRNA) are encapsidated inside the newly synthesized viral particle as a dimer. The interaction of Gag with the gRNA in the cytoplasm ensures its specific encapsidation. Targeting of the Gag–RNA complex to the plasma membrane (PM) is promoted by host transfer RNA (tRNA) binding to the Gag matrix (MA) domain. Since the spatio-temporal parameters of these related events remain unclear, this figure depicts the different possibilities. CA: capsid; NC: nucleocapsid; RT: reverse transcriptase; PR: protease; IN: integrase; CRM1: Chromosomal Maintenance 1; LTR: long terminal repeat.
Mentions: In order to generate an infectious particle, HIV-1 must selectively package two copies of its unspliced positive sense and single-stranded gRNA [8,9]. Genome encapsidation is highly specific, allowing the gRNA to be efficiently selected from a much larger pool of cellular and subgenomic viral RNA species (reviewed in [10,11]). This specificity is achieved through the recognition of cis-acting packaging signals by the Gag precursor protein which are also thought to be regulated by RNA conformational switches [12,13,14,15,16]. The major packaging signal comprises the 5′ untranslated region (UTR), the beginning of the Gag coding sequence [17,18,19,20,21,22,23], and may include other regions within the gRNA [24,25,26]. The gRNA is initially selected in the cytoplasm by a limited number of Gag molecules. The Gag–RNA complex then nucleates viral assembly at the plasma membrane. However, the spatio-temporal parameters of gRNA recognition and viral assembly remain incomplete (Figure 1).

View Article: PubMed Central - PubMed

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) replication is a highly regulated process requiring the recruitment of viral and cellular components to the plasma membrane for assembly into infectious particles. This review highlights the recent process of understanding the selection of the genomic RNA (gRNA) by the viral Pr55Gag precursor polyprotein, and the processes leading to its incorporation into viral particles.

No MeSH data available.