scholarly journals The Primary Nucleotide Sequence of the Bovine Leukemia Virus RNA Packaging Signal Can Influence Efficient RNA Packaging and Virus Replication

Virology ◽  
2002 ◽  
Vol 301 (2) ◽  
pp. 272-280 ◽  
Author(s):  
Louis M. Mansky ◽  
Lisa C. Gajary
Keyword(s):  
Nucleotide Sequence ◽  
Virus Replication ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Rna Packaging ◽  
Packaging Signal ◽  
Virus Rna ◽  
Rna Packaging Signal ◽  
Primary Nucleotide Sequence

scholarly journals Effects of Gag Mutation and Processing on Retroviral Dimeric RNA Maturation

2006 ◽  
Vol 80 (3) ◽  
pp. 1242-1249 ◽  
Author(s):  
William Fu ◽  
Que Dang ◽  
Kunio Nagashima ◽  
Eric O. Freed ◽  
Vinay K. Pathak ◽  
...  
Keyword(s):  
Viral Protein ◽  
Leukemia Virus ◽  
Viral Rna ◽  
Host Cells ◽  
Protein Cleavage ◽  
Rna Packaging ◽  
Virus Rna ◽  
Rna Dimer ◽  
Rna Maturation ◽  
Hiv 1

ABSTRACT After their release from host cells, most retroviral particles undergo a maturation process, which includes viral protein cleavage, core condensation, and increased stability of the viral RNA dimer. Inactivating the viral protease prevents protein cleavage; the resulting virions lack condensed cores and contain fragile RNA dimers. Therefore, protein cleavage is linked to virion morphological change and increased stability of the RNA dimer. However, it is unclear whether protein cleavage is sufficient for mediating virus RNA maturation. We have observed a novel phenotype in a murine leukemia virus capsid mutant, which has normal virion production, viral protein cleavage, and RNA packaging. However, this mutant also has immature virion morphology and contains a fragile RNA dimer, which is reminiscent of protease-deficient mutants. To our knowledge, this mutant provides the first evidence that Gag cleavage alone is not sufficient to promote RNA dimer maturation. To extend our study further, we examined a well-defined human immunodeficiency virus type 1 (HIV-1) Gag mutant that lacks a functional PTAP motif and produces immature virions without major defects in viral protein cleavage. We found that the viral RNA dimer in the PTAP mutant is more fragile and unstable compared with those from wild-type HIV-1. Based on the results of experiments using two different Gag mutants from two distinct retroviruses, we conclude that Gag cleavage is not sufficient for promoting RNA dimer maturation, and we propose that there is a link between the maturation of virion morphology and the viral RNA dimer.

scholarly journals Inhibition of Hepadnavirus Reverse Transcriptase-ε RNA Interaction by Porphyrin Compounds

2007 ◽  
Vol 82 (5) ◽  
pp. 2305-2312 ◽  
Author(s):  
Li Lin ◽  
Jianming Hu
Keyword(s):  
Reverse Transcriptase ◽  
Protoporphyrin Ix ◽  
Rna Packaging ◽  
Packaging Signal ◽  
B Virus ◽  
Protein Priming ◽  
Rna Interaction ◽  
Iron Protoporphyrin ◽  
Rna Packaging Signal ◽  
Viral Reverse Transcription

ABSTRACT The hepatitis B virus (HBV) reverse transcriptase (RT) plays a multitude of fundamental roles in the viral life cycle and is the key target in the development of anti-HBV chemotherapy. We report here that the endogenous small molecule iron protoporphyrin IX (hemin) and several related porphyrin compounds potently blocked a critical RT interaction with the viral RNA packaging signal/origin of replication, called ε. As RT-ε interaction is essential for the initiation of viral reverse transcription, which is primed by RT itself (protein priming), the porphyrin compounds dramatically suppressed the protein-priming reaction. Further studies demonstrated that these compounds could target the unique N-terminal domain of the RT protein, the so-called terminal protein. Hemin and related porphyrin compounds thus represent a novel class of agents that can block HBV RT functions through a mechanism and target that are completely distinct from those of existing anti-HBV drugs.

The gag and pol genes of bovine leukemia virus: Nucleotide sequence and analysis

Virology ◽  
1985 ◽  
Vol 142 (2) ◽  
pp. 357-377 ◽  
Author(s):  
Nancy R. Rice ◽  
Robert M. Stephens ◽  
Arséne Burny ◽  
Raymond V. Gilden
Keyword(s):  
Nucleotide Sequence ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus

scholarly journals Involvement of the Matrix and Nucleocapsid Domains of the Bovine Leukemia Virus Gag Polyprotein Precursor in Viral RNA Packaging

2003 ◽  
Vol 77 (17) ◽  
pp. 9431-9438 ◽  
Author(s):  
Huating Wang ◽  
Kendra M. Norris ◽  
Louis M. Mansky
Keyword(s):  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Viral Rna ◽  
Limited Information ◽  
Rna Packaging ◽  
Alanine Scanning Mutagenesis ◽  
Basic Residue ◽  
Gag Polyprotein ◽  
Human T Cell ◽  
Polyprotein Precursor

ABSTRACT The RNA packaging process for retroviruses involves a recognition event of the genome-length viral RNA by the viral Gag polyprotein precursor (PrGag), an important step in particle morphogenesis. The mechanism underlying this genome recognition event for most retroviruses is thought to involve an interaction between the nucleocapsid (NC) domain of PrGag and stable RNA secondary structures that form the RNA packaging signal. Presently, there is limited information regarding PrGag-RNA interactions involved in RNA packaging for the deltaretroviruses, which include bovine leukemia virus (BLV) and human T-cell leukemia virus types 1 and 2 (HTLV-1 and -2, respectively). To address this, alanine-scanning mutagenesis of BLV PrGag was done with a virus-like particle (VLP) system. As predicted, mutagenesis of conserved basic residues as well as residues of the zinc finger domains in the BLV NC domain of PrGag revealed residues that led to a reduction in viral RNA packaging. Interestingly, when conserved basic residues in the BLV MA domain of PrGag were mutated to alanine or glycine, but not when mutated to another basic residue, reductions in viral RNA packaging were also observed. The ability of PrGag to be targeted to the cell membrane was not affected by these mutations in MA, indicating that PrGag membrane targeting was not associated with the reduction in RNA packaging. These observations indicate that these basic residues in the MA domain of PrGag influence RNA packaging, without influencing Gag membrane localization. It was further observed that (i) a MA/NC double mutant had a more severe RNA packaging defect than either mutant alone, and (ii) RNA packaging was not found to be associated with transient localization of Gag in the nucleus. In summary, this report provides the first direct evidence for the involvement of both the BLV MA and NC domains of PrGag in viral RNA packaging.

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