scholarly journals Elucidation of a conserved RNA stem-loop structure in the packaging signal of human immunodeficiency virus type 1

FEBS Letters ◽  
1993 ◽  
Vol 327 (2) ◽  
pp. 213-218 ◽  
Author(s):  
Takuma Hayashi ◽  
Yoshio Ueno ◽  
Takashi Okamoto
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Loop Structure ◽  
Packaging Signal ◽  
Stem Loop ◽  
Stem Loop Structure ◽  
Immunodeficiency Virus

scholarly journals Analysis of Natural Variants of the Human Immunodeficiency Virus Type 1 gag-pol Frameshift Stem-Loop Structure

2002 ◽  
Vol 76 (15) ◽  
pp. 7868-7873 ◽  
Author(s):  
Amalio Telenti ◽  
Raquel Martinez ◽  
Miguel Munoz ◽  
Gabriela Bleiber ◽  
Gilbert Greub ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Replication ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Thermodynamic Stability ◽  
Stem Loop ◽  
Stem Loop Structure ◽  
Immunodeficiency Virus ◽  
Natural Variants

ABSTRACT Human immunodeficiency virus type 1 uses ribosomal frameshifting for translation of the Gag-Pol polyprotein. Frameshift activities are thought to be tightly regulated. Analysis of gag p1 sequences from 270 plasma virions identified in 64% of the samples the occurrence of polymorphism that could lead to changes in thermodynamic stability of the stem-loop. Expression in Saccharomyces cerevisiae of p1-β-galactosidase fusion proteins from 10 representative natural stem-loop variants and three laboratory mutant constructs (predicted the thermodynamic stability [ΔG°] ranging from −23.0 to −4.3 kcal/mol) identified a reduction in frameshift activity of 13 to 67% compared with constructs with the wild-type stem-loop (ΔG°, −23.5 kcal/mol). Viruses carrying stem-loops associated with greater than 60% reductions in frameshift activity presented profound defects in viral replication. In contrast, viruses with stem-loop structures associated with 16 to 42% reductions in frameshift efficiency displayed no significant viral replication deficit.

scholarly journals Possible Role of Dimerization in Human Immunodeficiency Virus Type 1 Genome RNA Packaging

2003 ◽  
Vol 77 (7) ◽  
pp. 4060-4069 ◽  
Author(s):  
Jun-Ichi Sakuragi ◽  
Shigeharu Ueda ◽  
Aikichi Iwamoto ◽  
Tatsuo Shioda
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Rna Packaging ◽  
Dimer Formation ◽  
Stem Loop ◽  
Immunodeficiency Virus ◽  
Lower Stem ◽  
Hiv 1

ABSTRACT The dimer initiation site/dimer linkage sequence (DIS/DLS) region in the human immunodeficiency virus type 1 (HIV-1) RNA genome is suggested to play important roles in various steps of the virus life cycle. However, due to the presence of a putative DIS/DLS region located within the encapsidation signal region (E/psi), it is difficult to perform a mutational analysis of DIS/DLS without affecting the packaging of RNA into virions. Recently, we demonstrated that duplication of the DIS/DLS region in viral RNA caused the production of partially monomeric RNAs in virions, indicating that the region indeed mediated RNA-RNA interaction. We utilized this system to assess the precise location of DIS/DLS in the 5′ region of the HIV-1 genome with minimum effect on RNA packaging. We found that the entire lower stem of the U5/L stem-loop was required for packaging, whereas the region important for dimer formation was only 10 bases long within the lower stem of the U5/L stem-loop. The R/U5 stem-loop was required for RNA packaging but was completely dispensable for dimer formation. The SL1 lower stem was important for both dimerization and packaging, but surprisingly, deletion of the palindromic sequence at the top of the loop only partially affected dimerization. These results clearly indicated that the E/psi of HIV-1 is much larger than the DIS/DLS and that the primary DIS/DLS is completely included in the E/psi. Therefore, it is suggested that RNA dimerization is a part of RNA packaging, which requires multiple steps.

scholarly journals Nucleolin and the Packaging Signal, ψ, Promote the Budding of Human Immunodeficiency Virus Type-1 (HIV-1)

2004 ◽  
Vol 48 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Tomonori Ueno ◽  
Kenzo Tokunaga ◽  
Hirofumi Sawa ◽  
Masae Maeda ◽  
Joe Chiba ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Packaging Signal ◽  
Immunodeficiency Virus ◽  
Hiv 1

scholarly journals Deletion of stem-loop 3 is compensated by second-site mutations within the Gag protein of human immunodeficiency virus type 1

Virology ◽  
2003 ◽  
Vol 314 (1) ◽  
pp. 221-228 ◽  
Author(s):  
Liwei Rong ◽  
Rodney S Russell ◽  
Jing Hu ◽  
Michael Laughrea ◽  
Mark A Wainberg ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Stem Loop ◽  
Gag Protein ◽  
Immunodeficiency Virus

scholarly journals trans-Complementation Rescue of Cyclophilin A-Deficient Viruses Reveals that the Requirement for Cyclophilin A in Human Immunodeficiency Virus Type 1 Replication Is Independent of Its Isomerase Activity

2002 ◽  
Vol 76 (5) ◽  
pp. 2255-2262 ◽  
Author(s):  
Andrew C. S. Saphire ◽  
Michael D. Bobardt ◽  
Philippe A. Gallay
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cyclophilin A ◽  
Virus Infectivity ◽  
Packaging Signal ◽  
Isomerase Activity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) requires the incorporation of cyclophilin A (CypA) for replication. CypA is packaged by binding to the capsid (CA) region of Gag. This interaction is disrupted by cyclosporine (CsA). Preventing CypA incorporation, either by mutations in the binding region of CA or by the presence of CsA, abrogates virus infectivity. Given that CypA possesses an isomerase activity, it has been proposed that CypA acts as an uncoating factor by destabilizing the shell of CA that surrounds the viral genome. However, because the same domain of CypA is responsible for both its isomerase activity and its capacity to be packaged, it has been challenging to determine if isomerase activity is required for HIV-1 replication. To address this issue, we fused CypA to viral protein R (Vpr), creating a Vpr-CypA chimera. Because Vpr is packaged via the p6 region of Gag, this approach bypasses the interaction with CA and allows CypA incorporation even in the presence of CsA. Using this system, we found that Vpr-CypA rescues the infectivity of viruses lacking CypA, either produced in the presence of CsA or mutated in the CypA packaging signal of CA. Furthermore, a Vpr-CypA mutant which has no isomerase activity and no capacity to bind to CA also rescues HIV-1 replication. Thus, this study demonstrates that the isomerase activity of CypA is not required for HIV-1 replication and suggests that the interaction of the catalytic site of CypA with CA serves no other function than to incorporate CypA into viruses.

scholarly journals Human Immunodeficiency Virus Type 1 Gag Polyprotein Modulates Its Own Translation

2006 ◽  
Vol 80 (21) ◽  
pp. 10478-10486 ◽  
Author(s):  
Emma C. Anderson ◽  
Andrew M. L. Lever
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Packaging Signal ◽  
Viral Particles ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The full-length viral RNA of human immunodeficiency virus type 1 (HIV-1) functions both as the mRNA for the viral structural proteins Gag and Gag/Pol and as the genomic RNA packaged within viral particles. The packaging signal which Gag recognizes to initiate genome encapsidation is in the 5′ untranslated region (UTR) of the HIV-1 RNA, which is also the location of translation initiation complex formation. Hence, it is likely that there is competition between the translation and packaging processes. We studied the ability of Gag to regulate translation of its own mRNA. Gag had a bimodal effect on translation from the HIV-1 5′ UTR, stimulating translation at low concentrations and inhibiting translation at high concentrations in vitro and in vivo. The inhibition was dependent upon the ability of Gag to bind the packaging signal through its nucleocapsid domain. The stimulatory activity was shown to depend on the matrix domain of Gag. These results suggest that Gag controls the equilibrium between translation and packaging, ensuring production of enough molecules of Gag to make viral particles before encapsidating its genome.

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