Construction of a Gammaretrovirus with a Novel Tropism and Wild-Type Replication Kinetics Capable of Using Human APJ as Entry Receptor

Bahrami, Shervin; Pagh, Kristina; Ejegod, Ditte Møller; Duch, Mogens; Tolstrup, Martin; Pedersen, Finn Skou

doi:10.1128/jvi.01028-12

Cited by 3 publications

(6 citation statements)

References 34 publications

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“…To study the adaptation of the apelin cassette when it is exposed to repeated passaging through one of its two receptors, both cell types were transduced with sterile filtered viral supernatant from transduced NIH 3T3 cells (16). In each passage, viral infection was allowed to establish itself for approximately 2 to 4 weeks after infection from the previous passage as illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…We have previously constructed a gammaretrovirus Env protein capable of infecting through either the human G protein-coupled receptor hAPJ or the murine G protein-coupled receptor Xpr1 (16). Here, we have monitored the adaptation of the Env protein when the virus is passaged through one of its two receptors.…”

Section: Discussionmentioning

confidence: 99%

“…We previously constructed the first example of a retargeted replication-competent gammaretrovirus (SL3-AP) capable of infecting through the human G protein-coupled receptor APJ (hAPJ) and the murine Xpr1 receptor with equal efficiencies (16). The replication-competent SL3-AP virus is based on the SL3-2 Env protein, which uses the xenotropic-polytropic receptor (Xpr1) for entry but, unlike other similar viruses, has a tropism restricted to rodent cells.…”

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confidence: 99%

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Directed Molecular Evolution of an Engineered Gammaretroviral Envelope Protein with Dual Receptor Use Shows Stable Maintenance of Both Receptor Specificities

Friis

Iturrioz

Thomsen

et al. 2016

J Virol

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We have previously reported the construction of a murine leukemia virus-based replication-competent gammaretrovirus (SL3-AP) capable of utilizing the human G protein-coupled receptor APJ (hAPJ) as its entry receptor and its natural receptor, the murine Xpr1 receptor, with equal affinities. The apelin receptor has previously been shown to function as a coreceptor for HIV-1, and thus, adaptation of the viral vector to this receptor is of significant interest. Here, we report the molecular evolution of the SL3-AP envelope protein when the virus is cultured in cells harboring either the Xpr1 or the hAPJ receptor. Interestingly, the dual receptor affinity is maintained even after 10 passages in these cells. At the same time, the chimeric viral envelope protein evolves in a distinct pattern in the apelin cassette when passaged on D17 cells expressing hAPJ in three separate molecular evolution studies. This pattern reflects selection for reduced ligand-receptor interaction and is compatible with a model in which SL3-AP has evolved not to activate hAPJ receptor internalization. IMPORTANCEFew successful examples of engineered retargeting of a retroviral vector exist. The engineered SL3-AP envelope is capable of utilizing either the murine Xpr1 or the human APJ receptor for entry. In addition, SL3-AP is the first example of an engineered retrovirus retaining its dual tropism after several rounds of passaging on cells expressing only one of its receptors. We demonstrate that the virus evolves toward reduced ligand-receptor affinity, which sheds new light on virus adaptation. We provide indirect evidence that such reduced affinity leads to reduced receptor internalization and propose a novel model in which too rapid receptor internalization may decrease virus entry. F usion of lipid membranes is not a spontaneous event and thus requires a supply of energy through an active fusion mechanism. Retroviruses are enveloped viruses and hence are strictly dependent on their fusion machinery for entry into host cells. In retroviruses, including murine leukemia virus (MLV), the fusion energy is stored in the envelope (Env) protein that is present in the membrane envelope surrounding the viral particle. Env consists of trimers of two subunits, the N-terminal surface (SU) subunit and the C-terminal transmembrane (TM) subunit. SU is responsible for recognizing and binding cellular receptor proteins, which differ among virus types and define their tropism. The SU and TM subunits remain associated through noncovalent interactions or, as for MLV, through a disulfide bridge that is broken as a result of disulfide isomerization following receptor binding (1). Here, the fusion energy stored in TM and suppressed by SU is released by conformational changes allowing the formation of an elongated triple helix in TM. This leads to insertion of the fusion peptide into the membrane of the host cell and hence induces membrane fusion (2), as reviewed in references 3 and 4. Other reports have suggested a need for proteolytic cleavage of SU in e...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Directed Molecular Evolution of an Engineered Gammaretroviral Envelope Protein with Dual Receptor Use Shows Stable Maintenance of Both Receptor Specificities

Friis

Iturrioz

Thomsen

et al. 2016

J Virol

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“…Through structural data of the ecotropic MLV glycoprotein and molecular modeling software, Li and colleagues were able to predict the successful insertion of somatostatin, a small peptide hormone, into the receptor-binding domain of ecotropic MLV SU in a manner that would preserve the majority of the Env structure, and, therefore, function (Figure 1E) [84]. A separate group has utilized structural data to incorporate the small peptide apelin into the FeLV-B related Env, SL3-2, and retarget entry to the apelin receptor, APJ [85]. These studies improve on an earlier peptide-retargeted Env, in which insertion of the SDF-1α peptide into the ecotropic MLV VRA directed entry to the CXCR4 receptor, albeit with a low titer [86].…”

Section: Targeting With Chimeric Env Proteinsmentioning

confidence: 99%

“…(F) Insertion of additional domains to either target or block the wild-type Env receptor-binding domain. For blocking domains, the cleavage by a host cell protease results in the release of the virus in the vicinity of the targeted cell [85–89]. Additional binding domains function to bind alternative receptors, but can allow the wild-type Env to function as a trigger for membrane fusion.…”

Section: Figurementioning

confidence: 99%

Library Screening and Receptor-Directed Targeting of Gammaretroviral Vectors

Mazari¹,

Roth²

2012

Future Microbiol.

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Gene- and cell-based therapies hold great potential for the advancement of the personalized medicine movement. Gene therapy vectors have made dramatic leaps forward since their inception. Retroviral-based vectors were the first to gain clinical attention and still offer the best hope for the long-term correction of many disorders. The fear of nonspecific transduction makes targeting a necessary feature for most clinical applications. However, this remains a difficult feature to optimize, with specificity often coming at the expense of efficiency. The aim of this article is to discuss the various methods employed to retarget retroviral entry. Our focus will lie on the modification of gammaretroviral envelope proteins with an in-depth discussion of the creation and screening of envelope libraries.

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Unique Structure and Distinctive Properties of the Ancient and Ubiquitous Gamma-Type Envelope Glycoprotein

Hogan

Johnson

2023

Viruses

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After the onset of the AIDS pandemic, HIV-1 (genus Lentivirus) became the predominant model for studying retrovirus Env glycoproteins and their role in entry. However, HIV Env is an inadequate model for understanding entry of viruses in the Alpharetrovirus, Gammaretrovirus and Deltaretrovirus genera. For example, oncogenic model system viruses such as Rous sarcoma virus (RSV, Alpharetrovirus), murine leukemia virus (MLV, Gammaretrovirus) and human T-cell leukemia viruses (HTLV-I and HTLV-II, Deltaretrovirus) encode Envs that are structurally and functionally distinct from HIV Env. We refer to these as Gamma-type Envs. Gamma-type Envs are probably the most widespread retroviral Envs in nature. They are found in exogenous and endogenous retroviruses representing a broad spectrum of vertebrate hosts including amphibians, birds, reptiles, mammals and fish. In endogenous form, gamma-type Envs have been evolutionarily coopted numerous times, most notably as placental syncytins (e.g., human SYNC1 and SYNC2). Remarkably, gamma-type Envs are also found outside of the Retroviridae. Gp2 proteins of filoviruses (e.g., Ebolavirus) and snake arenaviruses in the genus Reptarenavirus are gamma-type Env homologs, products of ancient recombination events involving viruses of different Baltimore classes. Distinctive hallmarks of gamma-type Envs include a labile disulfide bond linking the surface and transmembrane subunits, a multi-stage attachment and fusion mechanism, a highly conserved (but poorly understood) “immunosuppressive domain”, and activation by the viral protease during virion maturation. Here, we synthesize work from diverse retrovirus model systems to illustrate these distinctive properties and to highlight avenues for further exploration of gamma-type Env structure and function.

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Construction of a Gammaretrovirus with a Novel Tropism and Wild-Type Replication Kinetics Capable of Using Human APJ as Entry Receptor

Cited by 3 publications

References 34 publications

Directed Molecular Evolution of an Engineered Gammaretroviral Envelope Protein with Dual Receptor Use Shows Stable Maintenance of Both Receptor Specificities

Directed Molecular Evolution of an Engineered Gammaretroviral Envelope Protein with Dual Receptor Use Shows Stable Maintenance of Both Receptor Specificities

Library Screening and Receptor-Directed Targeting of Gammaretroviral Vectors

Unique Structure and Distinctive Properties of the Ancient and Ubiquitous Gamma-Type Envelope Glycoprotein

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