scholarly journals Equine Infectious Anemia Virus Gag Assembly and Export Are Directed by Matrix Protein throughtrans-Golgi Networks and Cellular Vesicles

2015 ◽  
Vol 90 (4) ◽  
pp. 1824-1838 ◽  
Author(s):  
Zeli Zhang ◽  
Jian Ma ◽  
Xiang Zhang ◽  
Chao Su ◽  
Qiu-Cheng Yao ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Matrix Protein ◽  
Equine Infectious Anemia Virus ◽  
Multivesicular Bodies ◽  
Microtubule Depolymerization ◽  
N Terminus ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Gag Assembly ◽  
Hiv 1

ABSTRACTGag intracellular assembly and export are very important processes for lentiviruses replication. Previous studies have demonstrated that equine infectious anemia virus (EIAV) matrix (MA) possesses distinct phosphoinositide affinity compared with HIV-1 MA and that phosphoinositide-mediated targeting to peripheral and internal membranes is a critical factor in EIAV assembly and release. In this study, we compared the cellular assembly sites of EIAV and HIV-1. We observed that the assembly of EIAV particles occurred on interior cellular membranes, while HIV-1 was targeted to the plasma membrane (PM) for assembly. Then, we determined that W7 and K9 in the EIAV MA N terminus were essential for Gag assembly and release but did not affect the cellular distribution of Gag. The replacement of EIAV MA with HIV-1 MA directed chimeric Gag to the PM but severely impaired Gag release. MA structural analysis indicated that the EIAV and HIV-1 MAs had similar spatial structures but that helix 1 of the EIAV MA was closer to loop 2. Further investigation indicated that EIAV Gag accumulated in thetrans-Golgi network (TGN) but not the early and late endosomes. The 9 N-terminal amino acids of EIAV MA harbored the signal that directed Gag to the TGN membrane system. Additionally, we demonstrated that EIAV particles were transported to the extracellular space by the cellular vesicle system. This type of EIAV export was not associated with multivesicular bodies or microtubule depolymerization but could be inhibited by the actin-depolymerizing drug cytochalasin D, suggesting that dynamic actin depolymerization may be associated with EIAV production.IMPORTANCEIn previous studies, EIAV Gag was reported to localize to both the cell interior and the plasma membrane. Here, we demonstrate that EIAV likely uses the TGN as the assembly site in contrast to HIV-1, which is targeted to the PM for assembly. These distinct assembly features are determined by the MA domain. We also identified two sites in the N terminus of EIAV MA that were important for Gag assembly and release. Furthermore, the observation of EIAV transport by cellular vesicles but not by multivesicular bodies sheds light on the mechanisms underlying EIAV cellular replication.

scholarly journals Functional Replacement and Positional Dependence of Homologous and Heterologous L Domains in Equine Infectious Anemia Virus Replication

2002 ◽  
Vol 76 (4) ◽  
pp. 1569-1577 ◽  
Author(s):  
Feng Li ◽  
Chaoping Chen ◽  
Bridget A. Puffer ◽  
Ronald C. Montelaro
Keyword(s):  
Life Cycle ◽  
Virus Particle ◽  
Matrix Protein ◽  
Particle Production ◽  
Equine Infectious Anemia Virus ◽  
Virus Infectivity ◽  
Gag Protein ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Hiv 1

ABSTRACT We have previously demonstrated by Gag polyprotein budding assays that the Gag p9 protein of equine infectious anemia virus (EIAV) utilizes a unique YPDL motif as a late assembly domain (L domain) to facilitate release of the budding virus particle from the host cell plasma membrane (B. A. Puffer, L. J. Parent, J. W. Wills, and R. C. Montelaro, J. Virol. 71:6541-6546, 1997). To characterize in more detail the role of the YPDL L domain in the EIAV life cycle, we have examined the replication properties of a series of EIAV proviral mutants in which the parental YPDL L domain was replaced by a human immunodeficiency virus type 1 (HIV-1) PTAP or Rous sarcoma virus (RSV) PPPY L domain in the p9 protein or by proviruses in which the parental YPDL or HIV-1 PTAP L domain was inserted in the viral matrix protein. The replication properties of these L-domain variants were examined with respect to Gag protein expression and processing, virus particle production, and virus infectivity. The data from these experiments indicate that (i) the YPDL L domain of p9 is required for replication competence (assembly and infectivity) in equine cell cultures, including the natural target equine macrophages; (ii) all of the functions of the YPDL L domain in the EIAV life cycle can be replaced by replacement of the parental YPDL sequence in p9 with the PTAP L-domain segment of HIV-1 p6 or the PPPY L domain of RSV p2b; and (iii) the assembly, but not infectivity, functions of the EIAV proviral YPDL substitution mutants can be partially rescued by inclusions of YPDL and PTAP L-domain sequences in the C-terminal region of the EIAV MA protein. Taken together, these data demonstrate that the EIAV YPDL L domain mediates distinct functions in viral budding and infectivity and that the HIV-1 PTAP and RSV PPPY L domains can effectively facilitate these dual replication functions in the context of the p9 protein. In light of the fact that YPDL, PTAP, and PPPY domains evidently have distinct characteristic binding specificities, these observations may indicate different portals into common cellular processes that mediate EIAV budding and infectivity, respectively.

scholarly journals Distinct Intracellular Trafficking of Equine Infectious Anemia Virus and Human Immunodeficiency Virus Type 1 Gag during Viral Assembly and Budding Revealed by Bimolecular Fluorescence Complementation Assays

2007 ◽  
Vol 81 (20) ◽  
pp. 11226-11235 ◽  
Author(s):  
Jing Jin ◽  
Timothy Sturgeon ◽  
Chaoping Chen ◽  
Simon C. Watkins ◽  
Ora A. Weisz ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Equine Infectious Anemia Virus ◽  
Bimolecular Fluorescence Complementation ◽  
Immunodeficiency Virus ◽  
Equine Infectious Anemia ◽  
Cellular Pathways ◽  
Anemia Virus ◽  
Gag Assembly ◽  
Hiv 1

ABSTRACT Retroviral Gag polyproteins are necessary and sufficient for virus budding. Numerous studies of human immunodeficiency virus type 1 (HIV-1) Gag assembly and budding mechanisms have been reported, but relatively little is known about these fundamental pathways among animal lentiviruses. While there may be a general assumption that lentiviruses share common assembly mechanisms, studies of equine infectious anemia virus (EIAV) have indicated alternative cellular pathways and cofactors employed among lentiviruses for assembly and budding. In the current study, we used bimolecular fluorescence complementation to characterize and compare assembly sites and budding efficiencies of EIAV and HIV-1 Gag in both human and rodent cells. The results of these studies demonstrated that replacing the natural RNA nuclear export element (Rev-response element [RRE]) used by HIV-1 and EIAV with the hepatitis B virus posttranscriptional regulatory element (PRE) altered HIV-1, but not EIAV, Gag assembly sites and budding efficiency in human cells. Consistent with this novel observation, different assembly sites were revealed in human cells for Rev-dependent EIAV and HIV-1 Gag polyproteins. In rodent cells, Rev-dependent HIV-1 Gag assembly and budding were blocked, but changing RRE to PRE rescued HIV-1 Gag assembly and budding. In contrast, EIAV Gag polyproteins synthesized from mRNA exported via either Rev-dependent or PRE-dependent mechanisms were able to assemble and bud efficiently in rodent cells. Taken together, our results suggest that lentivirus assembly and budding are regulated by the RNA nuclear export pathway and that alternative cellular pathways can be adapted for lentiviral Gag assembly and budding.

scholarly journals Structure of Equine Infectious Anemia Virus Matrix Protein

2002 ◽  
Vol 76 (4) ◽  
pp. 1876-1883 ◽  
Author(s):  
Hideki Hatanaka ◽  
Oleg Iourin ◽  
Zihe Rao ◽  
Elizabeth Fry ◽  
Alan Kingsman ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Equine Infectious Anemia Virus ◽  
Sequence Similarity ◽  
Membrane Binding ◽  
Host Cells ◽  
Immunodeficiency Virus ◽  
The Matrix ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Hiv 1

ABSTRACT The Gag polyprotein is key to the budding of retroviruses from host cells and is cleaved upon virion maturation, the N-terminal membrane-binding domain forming the matrix protein (MA). The 2.8-Å resolution crystal structure of MA of equine infectious anemia virus (EIAV), a lentivirus, reveals that, despite showing no sequence similarity, more than half of the molecule can be superimposed on the MAs of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV). However, unlike the structures formed by HIV-1 and SIV MAs, the oligomerization state observed is not trimeric. We discuss the potential of this molecule for membrane binding in the light of conformational differences between EIAV MA and HIV or SIV MA.

scholarly journals Mutation of YMYL in the Nipah Virus Matrix Protein Abrogates Budding and Alters Subcellular Localization

2006 ◽  
Vol 80 (24) ◽  
pp. 12070-12078 ◽  
Author(s):  
Michael J. Ciancanelli ◽  
Christopher F. Basler
Keyword(s):  
Matrix Protein ◽  
Ebola Virus ◽  
Equine Infectious Anemia Virus ◽  
Nipah Virus ◽  
Gag Protein ◽  
Late Domain ◽  
M Proteins ◽  
Equine Infectious Anemia ◽  
Infected Cells ◽  
Anemia Virus

ABSTRACT Matrix (M) proteins reportedly direct the budding of paramyxoviruses from infected cells. In order to begin to characterize the assembly process for the highly lethal, emerging paramyxovirus Nipah virus (NiV), we have examined the budding of NiV M. We demonstrated that expression of the NiV M protein is sufficient to produce budding virus-like particles (VLPs) that are physically and morphologically similar to NiV. We identified in NiV M a sequence, YMYL, with similarity to the YPDL late domain found in the equine infectious anemia virus Gag protein. When the YMYL within NiV M was mutated, VLP release was abolished and M was relocalized to the nucleus, but the mutant M proteins retained oligomerization activity. When YMYL was fused to a late-domain mutant of the Ebola virus VP40 matrix protein, VP40 budding was restored. These results suggest that the YMYL sequence may act as a trafficking signal and a late domain for NiV M.

scholarly journals Truncation of the cytoplasmic tail of equine infectious anemia virus increases virion production by improving Env cleavage and plasma membrane localization

2021 ◽  
Author(s):  
Xue-Feng Wang ◽  
Yu-Hong Wang ◽  
Bowen Bai ◽  
Mengmeng Zhang ◽  
Jie Chen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Equine Infectious Anemia Virus ◽  
Cytoplasmic Tail ◽  
Full Length ◽  
Functional Domain ◽  
Live Attenuated Vaccine ◽  
Virion Production ◽  
Equine Infectious Anemia ◽  
Anemia Virus

Envelope glycoproteins (Envs) of lentiviruses harbor unusually long cytoplasmic tails (CTs). Natural CT truncations always occur in vitro and are accompanied by attenuated virulence, but their effects on viral replication have not been fully elucidated. The Env in equine infectious anemia virus (EIAV) harbors the longest CT in the lentiviral family, and a truncated CT was observed in a live attenuated vaccine. This study demonstrates that CT truncation significantly increased EIAV production, as determined by comparing the virion yields from EIAV infectious clones in the presence or absence of the CT. A significant increase in a cleaved product from the CT-truncated Env precursor, but not the full-length Env, was observed. We further confirmed that the presence of the CT inhibited the cleavage of the Env precursor and found that a functional domain located at the C-terminus was responsible for this function. Moreover, CT-truncated Env was mainly localized at the plasma membrane (PM), while full-length Env was mainly localized in the cytoplasm. The CT-truncation caused a dramatic reduction in the endocytosis of Env. These results suggest that the CT can modulate the processing and trafficking of EIAV Env and thus regulate EIAV replication. Importance The mature lentivirus envelope glycoprotein (Env) is composed of a surface unit (SU) and a transmembrane unit (TM), which are cleaved products of the Env precursor. After mature Env is heterodimerically formed from the cleavage of the Env precursor, it is trafficked to the plasma membrane (PM) for incorporation and virion assembly. Env harbors a long cytoplasmic tail (CT), which has been increasingly found to play multiple roles in the Env biological cycle. Here, we revealed for the first time that the CT of equine infectious anemia virus (EIAV) Env inhibits cleavage of the Env precursor. Simultaneously, the CT promoted Env endocytosis, resulting in weakened Env localization at the PM. We also validated that the CT could significantly decrease EIAV production. These findings suggest that the CT regulates the processing and trafficking of EIAV Env to balance virion production.

scholarly journals S2 from Equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3

2016 ◽  
Author(s):  
Ajit Chande ◽  
Cristiana Cuccurullo ◽  
Annachiara Rosa ◽  
Serena Ziglio ◽  
Susan Carpenter ◽  
...  
Keyword(s):  
Equine Infectious Anemia Virus ◽  
Critical Role ◽  
Host Factor ◽  
Target Cells ◽  
Accessory Protein ◽  
Post Translational Modification ◽  
Virus Particles ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Hiv 1

ABSTRACTThe lentivirus equine infectious anemia virus (EIAV) encodes S2, a pathogenic determinant important for virus replication and disease progression in horses. No molecular function has yet been linked to this accessory protein. We now report that S2 can replace the activity of Nef on HIV-1 infectivity, being required to antagonize the inhibitory activity of SERINC proteins on Nef-defective HIV-1. Similar to Nef, S2 excludes SERINC5 from virus particles and requires an ExxxLL motif predicted to recruit the clathrin adaptor AP2. Accordingly, a functional endocytic machinery is essential for S2-mediated infectivity enhancement, which is impaired by inhibitors of clathrin-mediated endocytosis. In addition to retargeting SERINC5 to a late endosomal compartment, S2 promotes the host factor degradation. Emphasizing the similarity with Nef, we show that S2 is myristoylated and, compatible with a crucial role of the post-translational modification, its N-terminal glycine is required for the anti-SERINC5 activity.EIAV-derived vectors devoid of S2 are less susceptible than HIV-1 to the inhibitory effect of both human and equine SERINC5. We then identified the envelope glycoprotein of EIAV as a determinant which also modulates retrovirus susceptibility to SERINC5, indicating a bi-modular ability of the equine lentivirus to counteract the host factor.S2 shares no sequence homology with other retroviral factors known to counteract SERINC5. Adding to primate lentivirus Nef and gammaretrovirus glycoGag, the accessory protein from EIAV makes another example of a retroviral virulence determinant which independently evolved SERINC5-antagonizing activity. SERINC5 therefore plays a critical role for the interaction of the host with diverse retrovirus pathogens.Significance StatementSERINC5 and SERINC3 are recently discovered cellular inhibitors of retroviruses, which are incorporated into virus particles and impair their ability to propagate the infection to target cells. Only two groups of viruses (represented by HIV-1 and MLV) have so far been identified to have evolved the ability of counteracting SERINC inhibition. We now discovered that Equine infectious anemia virus, which causes a debilitating disease in horses, also acquired the ability to protect the virus particle from inhibition by SERINC5 and SERINC3, using its small protein S2. The evidence that three different retroviruses have independently evolved the ability to elude inhibition bySERINC5 and SERINC3 indicates that these cellular factors play a fundamental role against various retrovirus pathogens.

scholarly journals Equine Infectious Anemia Virus Utilizes Host Vesicular Protein Sorting Machinery during Particle Release

2003 ◽  
Vol 77 (15) ◽  
pp. 8440-8447 ◽  
Author(s):  
Giancarlo O. Tanzi ◽  
Andrew J. Piefer ◽  
Paul Bates
Keyword(s):  
Equine Infectious Anemia Virus ◽  
Leukemia Virus ◽  
Protein Sorting ◽  
Gag Protein ◽  
Particle Release ◽  
Late Domain ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Vacuolar Protein ◽  
Hiv 1

ABSTRACT A final step in retrovirus assembly, particle release from the cell, is modulated by a small motif in the Gag protein known as a late domain. Recently, human immunodeficiency virus type 1 (HIV-1) and Moloney murine leukemia virus (M-MuLV) were shown to require components of the cellular vacuolar protein sorting (VPS) machinery for efficient viral release. HIV-1 interacts with the VPS pathway via an association of HIV-1 Gag with TSG101, a component of the cellular complexes involved in VPS. Equine infectious anemia virus (EIAV) is unique among enveloped viruses studied to date because it utilizes a novel motif, YPDL in Gag, as a late domain. Our analysis of EIAV assembly demonstrates that EIAV Gag release is blocked by inhibition of the VPS pathway. However, in contrast to HIV-1, EIAV Gag release is insensitive to TSG101 depletion and EIAV particles do not contain significant levels of TSG101. Finally, we demonstrate that fusing EIAV Gag directly with another cellular component of the VPS machinery, VPS28, can restore efficient release of an EIAV Gag late-domain mutant. These results provide evidence that retroviruses can interact with the cellular VPS machinery in several different ways to accomplish particle release.

Binding of equine infectious anemia virus matrix protein to membrane bilayers involves multiple interactions

2000 ◽  
Vol 296 (3) ◽  
pp. 887-898 ◽  
Author(s):  
Paxton Provitera ◽  
Fadilla Bouamr ◽  
Diana Murray ◽  
Carol Carter ◽  
Suzanne Scarlata
Keyword(s):  
Matrix Protein ◽  
Equine Infectious Anemia Virus ◽  
Membrane Bilayers ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Multiple Interactions

scholarly journals S2 from equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3

2016 ◽  
Vol 113 (46) ◽  
pp. 13197-13202 ◽  
Author(s):  
Ajit Chande ◽  
Emilia Cristiana Cuccurullo ◽  
Annachiara Rosa ◽  
Serena Ziglio ◽  
Susan Carpenter ◽  
...  
Keyword(s):  
Equine Infectious Anemia Virus ◽  
Critical Role ◽  
Adaptor Protein ◽  
Inhibitory Effect ◽  
Host Factor ◽  
Accessory Protein ◽  
Endocytic Machinery ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Hiv 1

The lentivirus equine infectious anemia virus (EIAV) encodes the small protein S2, a pathogenic determinant that is important for virus replication and disease progression in horses. No molecular function had been linked to this accessory protein. We report that S2 can replace the activity of Negative factor (Nef) in HIV-1 infectivity, being required to antagonize the inhibitory activity of Serine incorporator (SERINC) proteins on Nef-defective HIV-1. Like Nef, S2 excludes SERINC5 from virus particles and requires an ExxxLL motif predicted to recruit the clathrin adaptor, Adaptor protein 2 (AP2). Accordingly, functional endocytic machinery is essential for S2-mediated infectivity enhancement, and S2-mediated enhancement is impaired by inhibitors of clathrin-mediated endocytosis. In addition to retargeting SERINC5 to a late endosomal compartment, S2 promotes host factor degradation. Emphasizing the similarity with Nef, we show that S2 is myristoylated, and, as is compatible with a crucial role in posttranslational modification, its N-terminal glycine is required for anti-SERINC5 activity. EIAV-derived vectors devoid of S2 are less susceptible than HIV-1 to the inhibitory effect of both human and equine SERINC5. We then identified the envelope glycoprotein of EIAV as a determinant that also modulates retroviral susceptibility to SERINC5, indicating that EIAV has a bimodal ability to counteract the host factor. S2 shares no sequence homology with other retroviral factors known to counteract SERINC5. Like the primate lentivirus Nef and the gammaretrovirus glycoGag, the accessory protein from EIAV is an example of a retroviral virulence determinant that independently evolved SERINC5-antagonizing activity. SERINC5 therefore plays a critical role in the interaction of the host with diverse retrovirus pathogens.

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