scholarly journals Retroviruses Human Immunodeficiency Virus and Murine Leukemia Virus Are Enriched in Phosphoinositides

2008 ◽  
Vol 82 (22) ◽  
pp. 11228-11238 ◽  
Author(s):  
Robin Chan ◽  
Pradeep D. Uchil ◽  
Jing Jin ◽  
Guanghou Shui ◽  
David E. Ott ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Membrane ◽  
Lipid Content ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Mass Spectrometry Analysis ◽  
Cell Periphery ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT Retroviruses acquire a lipid envelope during budding from the membrane of their hosts. Therefore, the composition of this envelope can provide important information about the budding process and its location. Here, we present mass spectrometry analysis of the lipid content of human immunodeficiency virus type 1 (HIV-1) and murine leukemia virus (MLV). The results of this comprehensive survey found that the overall lipid content of these viruses mostly matched that of the plasma membrane, which was considerably different from the total lipid content of the cells. However, several lipids are enriched in comparison to the composition of the plasma membrane: (i) cholesterol, ceramide, and GM3; and (ii) phosphoinositides, phosphorylated derivatives of phosphatidylinositol. Interestingly, microvesicles, which are similar in size to viruses and are also released from the cell periphery, lack phosphoinositides, suggesting a different budding mechanism/location for these particles than for retroviruses. One phosphoinositide, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], has been implicated in membrane binding by HIV Gag. Consistent with this observation, we found that PI(4,5)P2 was enriched in HIV-1 and that depleting this molecule in cells reduced HIV-1 budding. Analysis of mutant virions mapped the enrichment of PI(4,5)P2 to the matrix domain of HIV Gag. Overall, these results suggest that HIV-1 and other retroviruses bud from cholesterol-rich regions of the plasma membrane and exploit matrix/PI(4,5)P2 interactions for particle release from cells.

scholarly journals Evidence that Ecotropic Murine Leukemia Virus Contamination in TZM-bl Cells Does Not Affect the Outcome of Neutralizing Antibody Assays with Human Immunodeficiency Virus Type 1

2009 ◽  
Vol 83 (16) ◽  
pp. 8289-8292 ◽  
Author(s):  
Emily J. Platt ◽  
Miroslawa Bilska ◽  
Susan L. Kozak ◽  
David Kabat ◽  
David C. Montefiori
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT The TZM-bl cell line that is commonly used to assess neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) was recently reported to be contaminated with an ecotropic murine leukemia virus (MLV) (Y. Takeuchi, M. O. McClure, and M. Pizzato, J. Virol. 82:12585-12588, 2008), raising questions about the validity of results obtained with this cell line. Here we confirm this observation and show that HIV-1 neutralization assays performed with a variety of serologic reagents in a similar cell line that does not harbor MLV yield results that are equivalent to those obtained in TZM-bl cells. We conclude that MLV contamination has no measurable effect on HIV-1 neutralization when TZM-bl cells are used as targets for infection.

scholarly journals Targeting of Murine Leukemia Virus Gag to the Plasma Membrane Is Mediated by PI(4,5)P2/PS and a Polybasic Region in the Matrix

2009 ◽  
Vol 84 (1) ◽  
pp. 503-515 ◽  
Author(s):  
E. Hamard-Peron ◽  
F. Juillard ◽  
J. S. Saad ◽  
C. Roy ◽  
P. Roingeard ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Membrane ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Gag Proteins ◽  
Immunodeficiency Virus ◽  
The Matrix ◽  
Polybasic Region ◽  
Murine Leukemia

ABSTRACT Membrane targeting of the human immunodeficiency virus Gag proteins is dependent on phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] located in the plasma membrane. In order to determine if evolutionarily distant retroviral Gag proteins are targeted by a similar mechanism, we generated mutants of the matrix (MA) domain of murine leukemia virus (MuLV) Gag, examined their binding to membrane models in vitro, and analyzed their phenotypes in cell culture. In vitro, we showed that MA bound all the phosphatidylinositol phosphates with significant affinity but displayed a strong specificity for PI(4,5)P2 only if enhanced by phosphatidylserine. Mutations in the polybasic region in MA dramatically reduced this affinity. In cells, virus production was strongly impaired by PI(4,5)P2 depletion under conditions of 5ptaseIV overexpression, and mutations in the MA polybasic region altered Gag localization, membrane binding, and virion production. Our results suggest that the N-terminal polybasic cluster of MA is essential for Gag targeting to the plasma membrane. The binding of the MA domain to PI(4,5)P2 appears to be a conserved feature among retroviruses despite the fact that the MuLV-MA domain is structurally different from that of human immunodeficiency virus types 1 and 2 and lacks a readily identifiable PI(4,5)P2 binding cleft.

scholarly journals Cleavage of the Murine Leukemia Virus Transmembrane Env Protein by Human Immunodeficiency Virus Type 1 Protease: Transdominant Inhibition by Matrix Mutations

1998 ◽  
Vol 72 (12) ◽  
pp. 9621-9627 ◽  
Author(s):  
Rosemary E. Kiernan ◽  
Eric O. Freed
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Env Protein ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT We have identified mutations in the human immunodeficiency virus type 1 (HIV-1) matrix protein (MA) which block infectivity of virions pseudotyped with murine leukemia virus (MuLV) envelope (Env) glycoproteins without affecting infectivity conferred by HIV-1 Env or vesicular stomatitis virus G glycoproteins. This inhibition is very potent and displays a strong transdominant effect; infectivity is reduced more than 100-fold when wild-type and mutant molecular clones are cotransfected at a 1:1 ratio. This phenomenon is observed with both ecotropic and amphotropic MuLV Env. The MA mutations do not affect the incorporation of MuLV Env into virions. We demonstrate that in HIV-1 virions pseudotyped with MuLV Env, the HIV-1 protease (PR) efficiently catalyzes the cleavage of the p15(E) transmembrane (TM) protein to p12(E). Immunoprecipitation analysis of pseudotyped virions reveals that the mutant MA blocks this HIV-1 PR-mediated cleavage of MuLV TM. Furthermore, the transdominant inhibition exerted by the mutant MA on wild-type infectivity correlates with the relative level of p15(E) cleavage. Consistent with the hypothesis that abrogation of infectivity imposed by the mutant MA is due to inhibition of p15(E) cleavage, mutant virions are significantly more infectious when pseudotyped with a truncated p12(E) form of MuLV Env. These results indicate that HIV-1 Gag sequences can influence the viral PR-mediated processing of the MuLV TM Env protein p15(E). These findings have implications for the development of HIV-1-based retroviral vectors pseudotyped with MuLV Env, since p15(E) cleavage is essential for activating membrane fusion and virus infectivity.

scholarly journals Chimeric Human Immunodeficiency Virus Type 1 Containing Murine Leukemia Virus Matrix Assembles in Murine Cells

2002 ◽  
Vol 76 (1) ◽  
pp. 436-443 ◽  
Author(s):  
Margaret Reed ◽  
Roberto Mariani ◽  
Liana Sheppard ◽  
Katja Pekrun ◽  
Nathaniel R. Landau ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Cyclin T1 ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT Murine cells do not support efficient assembly and release of human immunodeficiency virus type 1 (HIV-1) virions. HIV-1-infected mouse cells that express transfected human cyclin T1 synthesize abundant Gag precursor polyprotein, but inefficiently assemble and release virions. This assembly defect may result from a failure of the Gag polyprotein precursor to target to the cell membrane. Plasma membrane targeting of the precursor is mediated by the amino-terminal region of polyprotein. To compensate for the assembly block, we substituted the murine leukemia virus matrix coding sequences into an infectious HIV-1 clone. Transfection of murine fibroblasts expressing cyclin T1 with the chimeric proviruses resulted in viruses that were efficiently assembled and released. Chimeric viruses, in which the cytoplasmic tail of the transmembrane subunit, gp41, was truncated to prevent potential interference between the envelope glycoprotein and the heterologous matrix, could infect human and murine cells. They failed to further replicate in the murine cells, but replicated with delayed kinetics in human MT-4 cells. These findings may be useful for establishing a murine model for HIV-1 replication.

scholarly journals The Retroviruses Human Immunodeficiency Virus Type 1 and Moloney Murine Leukemia Virus Adopt Radically Different Strategies To Regulate Promoter-Proximal Polyadenylation

2001 ◽  
Vol 75 (23) ◽  
pp. 11735-11746 ◽  
Author(s):  
Andre Furger ◽  
Joan Monks ◽  
Nick J. Proudfoot
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
Immunodeficiency Virus ◽  
A Site ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT Maximal gene expression in retroviruses requires that polyadenylation in the 5′ long terminal repeat (LTR) is suppressed. In human immunodeficiency virus type 1 (HIV-1) the promoter-proximal poly(A) site is blocked by interaction of U1 snRNP with the closely positioned major splice donor site (MSD) 200 nucleotides downstream. Here we investigated whether the same mechanism applies to down-regulate 5′ LTR polyadenylation in Moloney murine leukemia virus (MoMLV). Although the same molecular architecture is present in both viruses, the MoMLV poly(A) signal in the 5′ LTR is active whether or not the MSD is mutated. This surprising difference between the two retroviruses is not due to their actual poly(A) signals or MSD sequences, since exchange of either element between the two viral sequences does not alter their ability to regulate 5′ LTR poly(A) site use. Instead we demonstrate that sequence between the cap and AAUAAA is required for MSD-dependent poly(A) regulation in HIV-1, indicating a key role for this part of the LTR in poly(A) site suppression. We also show that the MoMLV poly(A) signal is an intrinsically weak RNA-processing signal. This suggests that in the absence of a poly(A) site suppression mechanism, MoMLV is forced to use a weak poly(A) signal.

scholarly journals Revealing Domain Structure through Linker-Scanning Analysis of the Murine Leukemia Virus (MuLV) RNase H and MuLV and Human Immunodeficiency Virus Type 1 Integrase Proteins

2006 ◽  
Vol 80 (19) ◽  
pp. 9497-9510 ◽  
Author(s):  
Jennifer Puglia ◽  
Tan Wang ◽  
Christine Smith-Snyder ◽  
Marie Cote ◽  
Michael Scher ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Rnase H ◽  
C Terminus ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT Linker-scanning libraries were generated within the 3′ terminus of the Moloney murine leukemia virus (M-MuLV) pol gene encoding the connection-RNase H domains of reverse transcriptase (RT) as well as the structurally related M-MuLV and human immunodeficiency virus type 1 (HIV-1) integrase (IN) proteins. Mutations within the M-MuLV proviral vectors were Tn7 based and resulted in 15-bp insertions. Mutations within an HIV-1 IN bacterial expression vector were based on Tn5 and resulted in 57-bp insertions. The effects of the insertions were examined in vivo (M-MuLV) and in vitro (HIV-1). A total of 178 individual M-MuLV constructs were analyzed; 40 in-frame insertions within RT connection-RNase H, 108 in-frame insertions within IN, 13 insertions encoding stop codons within RNase H, and 17 insertions encoding stop codons within IN. For HIV-1 IN, 56 mutants were analyzed. In both M-MuLV and HIV-1 IN, regions are identified which functionally tolerate multiple-linker insertions. For MuLV, these correspond to the RT-IN proteolytic junction, the junction between the IN core and C terminus, and the C terminus of IN. For HIV-1 IN, in addition to the junction between the IN core and C terminus and the C terminus of IN, insertions between the N terminus and core domains maintained integration and disintegration activity. Of the 40 in-frame insertions within the M-MuLV RT connection-RNase H domains, only the three C-terminal insertions mapping to the RT-IN proteolytic junction were viable. These results correlate with deletion studies mapping the domain and subdomain boundaries of RT and IN. Importantly, these genetic footprints provide a means to identify nonessential regions within RT and IN for targeted gene therapy applications.

scholarly journals ATPγS Disrupts Human Immunodeficiency Virus Type 1 Virion Core Integrity

2005 ◽  
Vol 79 (9) ◽  
pp. 5557-5567 ◽  
Author(s):  
Cagan Gurer ◽  
Anders Höglund ◽  
Stefan Höglund ◽  
Jeremy Luban
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Reverse Transcription ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia ◽  
Virion Core

ABSTRACT Heat shock protein 70 (Hsp70) is incorporated within the membrane of primate lentiviral virions. Here we demonstrate that Hsp70 is also incorporated into oncoretroviral virions and that it remains associated with membrane-stripped human immunodeficiency virus type 1 (HIV-1) virion cores. To determine if Hsp70 promotes virion infectivity, we attempted to generate Hsp70-deficient virions with gag deletion mutations, Hsp70 transdominant mutants, or RNA interference, but these efforts were confounded, largely because they disrupt virion assembly. Given that polypeptide substrates are bound and released by Hsp70 in an ATP-hydrolytic reaction cycle, we supposed that incubation of HIV-1 virions with ATP would perturb Hsp70 interaction with substrates in the virion and thereby decrease infectivity. Treatment with ATP or ADP had no observable effect, but ATPγS and GTPγS, nucleotide triphosphate analogues resistant to Hsp70 hydrolysis, dramatically reduced the infectivity of HIV-1 and murine leukemia virus virions. ATPγS-treated virions were competent for fusion with susceptible target cells, but viral cDNA synthesis was inhibited to an extent that correlated with the magnitude of decrease in infectivity. Intravirion reverse transcription by HIV-1, simian immunodeficiency virus, or murine leukemia virus was also inhibited by ATPγS. The effects of ATPγS on HIV-1 reverse transcription appeared to be indirect, resulting from disruption of virion core morphology that was evident by transmission electron microscopy. Consistent with effects on capsid conformation, ATPγS-treated viruslike particles failed to saturate host antiviral restriction activity. Our observations support a model in which the catalytic activity of virion-associated Hsp70 is required to maintain structural integrity of the virion core.

scholarly journals SERINC5 as a New Restriction Factor for Human Immunodeficiency Virus and Murine Leukemia Virus

2018 ◽  
Vol 5 (1) ◽  
pp. 323-340 ◽  
Author(s):  
Claudia Firrito ◽  
Cinzia Bertelli ◽  
Teresa Vanzo ◽  
Ajit Chande ◽  
Massimo Pizzato
Keyword(s):  
Human Immunodeficiency Virus ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Transmembrane Proteins ◽  
Target Cells ◽  
Restriction Factors ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Human Immunodeficiency Virus 1 ◽  
Murine Leukemia

SERINC genes encode for homologous multipass transmembrane proteins with unknown cellular function, despite being highly conserved across eukaryotes. Among the five SERINC genes found in humans, SERINC5 was shown to act as a powerful inhibitor of retroviruses. It is efficiently incorporated into virions and blocks the penetration of the viral core into target cells, by impairing the fusion process with a yet unclear mechanism. SERINC5 was also found to promote human immunodeficiency virus 1 (HIV-1) virion neutralization by antibodies, indicating a pleiotropic activity, which remains mostly unexplored. Counteracting factors have emerged independently in at least three retrovirus lineages, underscoring their fundamental importance during retrovirus evolution. Nef and S2 of primate and equine lentiviruses, and glycoGag of gammaretroviruses, act similarly by targeting SERINC5 to endosomes and excluding it from virions. Here, we discuss the features that distinguish SERINC5 from other known restriction factors, delineating a yet unique class of antiviral inhibitors.

scholarly journals Capsid Is a Dominant Determinant of Retrovirus Infectivity in Nondividing Cells

2004 ◽  
Vol 78 (11) ◽  
pp. 5670-5678 ◽  
Author(s):  
Masahiro Yamashita ◽  
Michael Emerman
Keyword(s):  
Human Immunodeficiency Virus ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Immunodeficiency Virus ◽  
Interphase Cells ◽  
Hiv Type 1 ◽  
The Difference ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT A major difference between lentiviruses such as human immunodeficiency virus (HIV) and most other retroviruses is their ability to productively infect nondividing cells. We present here genetic evidence for involvement of the capsid protein (CA) in the infectious phenotype in nondividing cells. A chimeric HIV type 1 (HIV-1) in which the MA and CA of HIV-1 are replaced with the MA, p12, and CA encoding sequences from murine leukemia virus (MLV) loses the ability to efficiently infect nondividing cells. Analysis of the accumulation of two-long-terminal-repeat circles implies that the impairment of nuclear transport of preintegration complexes is responsible for the restricted infection of this chimeric virus in nondividing cells. Incorporation of MLV MA and MLV p12 into HIV virions alone does not exert any adverse effects on viral infection in interphase cells. These results suggest that CA is the dominant determinant for the difference between HIV and MLV in the ability to transduce nondividing cells.

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