Feline oncornavirus-associated cell membrane antigen: evidence for an immunologically crossreactive feline sarcoma virus-coded protein.

Stephenson, John; Khan, Arifa S.; Sliski, Ann; Essex, Max

doi:10.1073/pnas.74.12.5608

Cited by 95 publications

(63 citation statements)

References 16 publications

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“…In the mature virus, in which Pr655ag has been cleaved to the viral structural proteins, the NH2-terminal fatty acid modification of p15 may serve to stabilize the viral membrane. The hydrophobic character and membrane association of p15 have been documented (23,24 (27), and P85gag-fes from Snyder-Theilen feline sarcoma virus (28,29) (numerous other examples are listed in ref. 25).…”

Section: Discussionmentioning

confidence: 99%

Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Henderson

Krutzsch

Oroszlan

1983

Proc. Natl. Acad. Sci. U.S.A.

234

140

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The primary structure of the NH2-terminal region of the gag gene encoded internal membrane-associated protein p15 has been determined for both Rauscher and Moloney murine leukemia viruses. Peptides generated by endopeptidases and purified by HPLC were subjected to semi-automated Edman degradation. Dipeptides obtained with dipeptidyl carboxypeptidase were identified by gas chromatography-mass spectrometry. The amino acid sequence of the first 16-residue segment of Rauscher p15 is identical to the sequence of Moloney p15 except for a single amino acid substitution (Gly-* Asp) at position 13. Both proteins were found to have an acylated NH2 terminus. By mass spectroscopy, myristic acid [CH3(CH2)12COOH] was found to be bound through an amide linkage to the NH2-terminal glycyl residue in both pl5s. The results ofliquid chromatography show that the NH2-terminal myristyl group greatly contributes to the strong binding of these modified proteins and peptides to hydrophobic surfaces. Because p15 is known to be derived from the NH2-terminal region of a precursor polyprotein Pr659'9 by proteolytic cleavage in the assembled virus, it is suggested that myristylation in vivo takes place during the biosynthesis ofPr659'9. Preliminary data indicate that such modification ofgag precursor polyproteins may be common to mammalian retroviruses. The role of NH2-terminal myristyl acylation of Pr65"ag in virus assembly and the possibility ofsimilar NH2-terminal modifications ofgag-related fusion proteins of transforming viruses are discussed.Type C murine leukemia viruses (MuLV) are representatives of a morphologically and biochemically defined group of RNA viruses (family Retroviridae) which replicate via a DNA intermediate synthesized by the virus-encoded enzyme reverse transcriptase (for review see ref. 1). Viruses of the Retroviridae family have been associated with animal and human leukemia and other types of cancer (for review see refs. 2 and 3).The type C MuLVs are composed of a RNA and a protein inner core structure encapsulated by a lipoprotein envelope. The inner core structural proteins of type C MuLVs are synthesized as a precursor polyprotein designated Pr65'ag. In the process of virus assembly, Pr659ag is associated with the inner plasma membrane where it also forms a specific complex with viral RNA. During subsequent viral budding and maturation,

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Section: Discussionmentioning

confidence: 99%

Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Henderson

Krutzsch

Oroszlan

1983

Proc. Natl. Acad. Sci. U.S.A.

234

140

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“…It is known that infected cats are able to elicit antibodies against different components of FeLV (18)(19)(20)(21)(22). However, until now the detection of antibodies to FeLV had limited significance for several reasons: first, there is no evidence that reliable antibody detection can predict FeLV infection; second, it is not known which antibodies are suitable; and third, the existence of endogenous FeLV (enFeLV) is widespread in cat populations in that every cell in every single cat harbors multiple copies of enFeLV (23,24).…”

mentioning

confidence: 99%

Detection of Antibodies to the Feline Leukemia Virus (FeLV) Transmembrane Protein p15E: an Alternative Approach for Serological FeLV Detection Based on Antibodies to p15E

et al. 2014

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The aim of this report was to investigate whether the diagnosis of feline leukemia virus (FeLV) infection by serology might be feasible and useful. Among the various viral proteins, the FeLV env-gene product (SU) and the envelope transmembrane protein p15E were considered promising candidates for the serological diagnosis of FeLV infection. Thus, we evaluated p15E and three other FeLV antigens, namely, a recombinant env-gene product, whole FeLV, and a short peptide from the FeLV transmembrane protein, for their potential to detect FeLV infection. To evaluate possible exposure of cats to FeLV, we tested serum and plasma samples from experimentally and naturally infected and vaccinated cats for the presence of antibodies to these antigens by enzyme-linked immunosorbent assays (ELISAs). The serological results were compared with the p27 and proviral real-time PCR results. We found that p15E displayed a diagnostic sensitivity of 95.7% and a specificity of 100% in experimentally infected cats. In naturally infected cats, p15E showed a diagnostic sensitivity of 77.1% and a specificity of 85.6%. Vaccinated cats displayed minimal antibody levels to p15E, suggesting that anti-p15E antibodies indicate infection rather than vaccination. The other antigens turned out to be too unspecific. The lower specificity in cats exposed to FeLV under field conditions may be explained by the fact that some cats become infected and seroconvert in the absence of detectable viral nucleic acids in plasma. We conclude that p15E serology may become a valuable tool for diagnosing FeLV infection; in some cases, it may replace PCR.

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“…As described earlier for other systems, anti-gp7O has no precipitating activity for the polyprotein (6,22). Antiserum produced by the donor cat detected what was apparently the same 46 gag-x protein both before (designated anti-STaut), and after (designated anti-ST-X), exhaustive absorption with FeLV (Fig.…”

Section: Establishment and Characterization Of A Melanoma Cellmentioning

confidence: 98%

“…To rule out the possibility that the gag- (6,(22)(23)(24)(25). 'Previous reports on the detection ofFeSV gagx polyproteins have utilized only antisera directly to the gag portions ofthe molecule or antisera ofnonfeline origin that were directed to the x portion ofthe molecule (23)(24)(25).…”

Section: Establishment and Characterization Of A Melanoma Cellmentioning

confidence: 99%

“…It has been postulated that each may be associated with a particular pathway of differentiation (5). The class ofprotein most characteristically identified as encoded by the transforming virus genome is the "gag-x" polyprotein, which contains a portion of gag virus structural proteins and a nonstructural protein, x, which appears to be expressed coordinately with malignant transformation (6)(7)(8).…”

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confidence: 99%

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Retrovirus-encoded transformation-specific polyproteins: expression coordinated with malignant phenotype in cells from different germ layers.

Chen

Essex

Shadduck

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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A transformation-associated polyprotein designated "gag-x" was previously shown to be induced by the feline sarcoma virus (FeSV) after the nonproductive transformation of rat or mink cells. We found that this protein was also expressed in cells derived from the native species (cat) with or without the production of feline leukemia helper virus (FeLV) and that cats could mount a humoral antibody response to the transformationspecific (x) portion ofthe molecule. Such antisera also reacted with the feline oncornavirus-associated cell membrane antigen (FOCMA) by membrane immunofluorescence. Expression of the gag-x protein was coordinated with malignant phenotype in that both transformed cat fibroblasts and cultured cells from a FeSV-induced melanoma expressed antigenically indistinguishable proteins of the same size. These cells are derived from different embryonic germ layers, suggesting that such transformation-related proteins may function in a pleiotropic manner when introduced by a virus.

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Feline oncornavirus-associated cell membrane antigen: evidence for an immunologically crossreactive feline sarcoma virus-coded protein.

Abstract: The feline oncornavirus-associated cell membrane antigen (FOCMA)

Cited by 95 publications

References 16 publications

Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Detection of Antibodies to the Feline Leukemia Virus (FeLV) Transmembrane Protein p15E: an Alternative Approach for Serological FeLV Detection Based on Antibodies to p15E

Retrovirus-encoded transformation-specific polyproteins: expression coordinated with malignant phenotype in cells from different germ layers.

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