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Feline tetherin is characterized by a short N-terminal region and is counteracted by the feline immunodeficiency virus envelope glycoprotein.

ABSTRACT: Tetherin (BST2) is the host cell factor that blocks the particle release of some enveloped viruses. Two putative feline tetherin proteins differing at the level of the N-terminal coding region have recently been described and tested for their antiviral activity. By cloning and comparing the two reported feline tetherins (called here cBST2(504) and cBST2*) and generating specific derivative mutants, this study provides evidence that feline tetherin has a shorter intracytoplasmic domain than those of other known homologues. The minimal tetherin promoter was identified and assayed for its ability to drive tetherin expression in an alpha interferon-inducible manner. We also demonstrated that cBST2(504) is able to dimerize, is localized at the cellular membrane, and impairs human immunodeficiency virus type 1 (HIV-1) particle release, regardless of the presence of the Vpu antagonist accessory protein. While cBST2(504) failed to restrict wild-type feline immunodeficiency virus (FIV) egress, FIV mutants, bearing a frameshift at the level of the envelope-encoding region, were potently blocked. The transient expression of the FIV envelope glycoprotein was able to rescue mutant particle release from feline tetherin-positive cells but did not antagonize human BST2 activity. Moreover, cBST2(504) was capable of specifically immunoprecipitating the FIV envelope glycoprotein. Finally, cBST2(504) also exerted its function on HIV-2 ROD10 and on the simian immunodeficiency virus SIVmac239. Taken together, these results show that feline tetherin does indeed have a short N-terminal region and that the FIV envelope glycoprotein is the predominant factor counteracting tetherin restriction.

SUBMITTER: Celestino M

PROVIDER: S-EPMC3393548 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Feline tetherin is characterized by a short N-terminal region and is counteracted by the feline immunodeficiency virus envelope glycoprotein.

Celestino Michele M Calistri Arianna A Del Vecchio Claudia C Salata Cristiano C Chiuppesi Flavia F Pistello Mauro M Borsetti Alessandra A Palù Giorgio G Parolin Cristina C

Journal of virology 20120418 12

Tetherin (BST2) is the host cell factor that blocks the particle release of some enveloped viruses. Two putative feline tetherin proteins differing at the level of the N-terminal coding region have recently been described and tested for their antiviral activity. By cloning and comparing the two reported feline tetherins (called here cBST2(504) and cBST2*) and generating specific derivative mutants, this study provides evidence that feline tetherin has a shorter intracytoplasmic domain than those ...[more]

PMID: 22514338

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Project description:BST2/tetherin inhibits the release of enveloped viruses from cells. Primate lentiviruses have evolved specific antagonists (Vpu, Nef, and Env). Here we characterized tetherin proteins of species representing both branches of the order Carnivora. Comparison of tiger and cat (Feliformia) to dog and ferret (Caniformia) genes demonstrated that the tiger and cat share a start codon mutation that truncated most of the tetherin cytoplasmic tail early in the Feliformia lineage (19 of 27 amino acids, including the dual tyrosine motif). Alpha interferon (IFN-?) induced tetherin and blocked feline immunodeficiency virus (FIV) replication in lymphoid and nonlymphoid feline cells. Budding of bald FIV and HIV particles was blocked by carnivore tetherins. However, infectious FIV particles were resistant, and spreading FIV replication was uninhibited. Antagonism mapped to the envelope glycoprotein (Env), which rescued FIV from carnivore tetherin restriction when expressed in trans but, in contrast to known antagonists, did not rescue noncognate particles. Also unlike the primate lentiviral antagonists, but similar to the Ebola virus glycoprotein, FIV Env did not reduce intracellular or cell surface tetherin levels. Furthermore, FIV-enveloped FIV particles actually required tetherin for optimal release from cells. The results show that FIV Envs mediate a distinctive tetherin evasion. Well adapted to a phylogenetically ancient tetherin tail truncation in the Felidae, it requires functional virion incorporation of Env, and it shields the budding particle without downregulating plasma membrane tetherin. Moreover, FIV has evolved dependence on this protein: particles containing FIV Env need tetherin for optimal release from the cell, while Env(-) particles do not.HIV-1 antagonizes the restriction factor tetherin with the accessory protein Vpu, while HIV-2 and the filovirus Ebola use their envelope (Env) glycoproteins for this purpose. It turns out that the FIV tetherin antagonist is also its Env protein, but the mechanism is distinctive. Unlike other tetherin antagonists, FIV Env cannot act in trans to rescue vpu-deficient HIV-1. It must be incorporated specifically into FIV virions to be active. Also unlike other retroviral antagonists, but similar to Ebola virus Env, it does not act by downregulating or degrading tetherin. FIV Env might exclude tetherin locally or direct assembly to tetherin-negative membrane domains. Other distinctive features are apparent, including evidence that this virus evolved an equilibrium in which tetherin is both restriction factor and cofactor, as FIV requires tetherin for optimal particle release.

Project description:Feline immunodeficiency virus (FIV) Vif protein counteracts feline APOBEC3s (FcaA3s) restriction factors by inducing their proteasomal degradation. The functional domains in FIV Vif for interaction with FcaA3s are poorly understood. Here, we have identified several motifs in FIV Vif that are important for selective degradation of different FcaA3s. Cats (Felis catus) express three types of A3s: single-domain A3Z2, single-domain A3Z3, and double-domain A3Z2Z3. We proposed that FIV Vif would selectively interact with the Z2 and the Z3 A3s. Indeed, we identified two N-terminal Vif motifs (12LF13 and 18GG19) that specifically interacted with the FcaA3Z2 protein but not with A3Z3. In contrast, the exclusive degradation of FcaA3Z3 was regulated by a region of three residues (M24, L25, and I27). Only a FIV Vif carrying a combination of mutations from both interaction sites lost the capacity to degrade and counteract FcaA3Z2Z3. However, alterations in the specific A3s interaction sites did not affect the cellular localization of the FIV Vif protein and binding to feline A3s. Pulldown experiments demonstrated that the A3 binding region localized to FIV Vif residues 50 to 80, outside the specific A3 interaction domain. Finally, we found that the Vif sites specific to individual A3s are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in the FIV Vif of pumas. Our data support a complex model of multiple Vif-A3 interactions in which the specific region for selective A3 counteraction is discrete from a general A3 binding domain.Both human immunodeficiency virus (HIV) and feline immunodeficiency virus (FIV) Vif proteins counteract their host's APOBEC3 restriction factors. However, these two Vif proteins have limited sequence homology. The molecular interaction between FIV Vif and feline APOBEC3s are not well understood. Here, we identified N-terminal FIV Vif sites that regulate the selective interaction of Vif with either feline APOBEC3Z2 or APOBEC3Z3. These specific Vif sites are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in FIV Vif from puma. Our findings provide important insights for future experiments describing the FIV Vif interaction with feline APOBEC3s and also indicate that the conserved feline APOBEC3s interaction sites of FIV Vif allow FIV transmissions in Felidae.

Dataset Information

Feline tetherin is characterized by a short N-terminal region and is counteracted by the feline immunodeficiency virus envelope glycoprotein.

Publications

Feline tetherin is characterized by a short N-terminal region and is counteracted by the feline immunodeficiency virus envelope glycoprotein.

Similar Datasets

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