Comparative studies on the structural phosphoproteins of mammalian type C viruses

Pal, Bijay K.; McAllister, Robert M.; Gardner, M. B.; Roy-Burman, Pradip

doi:10.1128/jvi.16.1.123-131.1975

Cited by 76 publications

(15 citation statements)

References 37 publications

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“…The ppl2 of 292 field isolate was also used to determine peptide homology between the nonphosphorylated and variously phosphorylated ppl2 species. The pp12 purified from 292 virus, labeled with 3H-amino acids and [32P]phosphate (13,14), was resolved by DEAE-cellulose chromatography (18) into three major peaks. One was non-phosphorylated, and the other two varied in the degree of phosphorylation (data not shown).…”

Section: ~~~~~~~~~-mentioning

confidence: 99%

“…Structural proteins of type C RNA tumor viruses consist of a major high-molecular-weight glycoprotein and several low-molecular-weight non-glycosylated proteins. One of the non-glycosylated proteins has been shown to be the major structural phosphoprotein of the virion (13,14). In viruses of lower mammalian species, including mice, rats, cats, minks, and pigs, the 12,000-dalton protein (p12) is always phosphorylated (ppl2) (13, 14; our unpublished data).…”

mentioning

confidence: 94%

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RNA tumor virus phosphoproteins: primary structural analysis and identification of phosphopeptides

Pal¹,

Bryant²,

Roy-Burman³

1978

J Virol

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Two-dimensional tryptic peptide mapping was used to compare the peptide sequences of the phosphoprotein (pp12) of cloned ecotropic and amphotropic wild mouse leukemia viruses, strains 1504 and 292. The maps of two ecotropic isolates were very similar to one another, as were the maps of two amphotropic isolates. There was also extensive similarity between the maps of this protein from ecotropic and amphotropic viruses, although characteristic peptide differences were readily recognized. These differences were consistent with the general type specificity of oncovirus phosphoproteins. The pp12 of the field isoalte of 292 virus contained five phosphopeptides, and the non-phosphorylated and variously phosphorylated species of this pp12 showed identical peptide maps, indicating differential phosphorylation of a single polypeptide.

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Section: ~~~~~~~~~-mentioning

confidence: 99%

mentioning

confidence: 94%

RNA tumor virus phosphoproteins: primary structural analysis and identification of phosphopeptides

Pal¹,

Bryant²,

Roy-Burman³

1978

J Virol

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“…Continuing the analogy with murine type C viruses, Long et al (21) have observed that MMTV p14 (p12) binds efficiently to singlestranded DNA and may, therefore, be analogous to murine type C virus plO (4,14). The further comparisons of MMTV p25 with RLV p30 as the major core protein, MMTV pp2O with RLV ppl2 as the major virion phosphoprotein (16,28), and MMTV plO with RLV p15 as the only virion envelope-associated polypeptide coded for by the gag regions of their respective virion genomes indicate further analogy (7,36). The order of gag proteins in the RLV gag precursor, Pr65sas, has been shown to be H2N-p15-ppl2-p30-plO-COOH (3,24,31).…”

Section: Labeling Of Virion Proteins With [32p]phos-mentioning

confidence: 96%

Polyprotein Precursors to Mouse Mammary Tumor Virus Proteins

Anderson

Naso

Davis

et al. 1979

J Virol

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Mouse mammary tumor virus (MMTV) derived from the culture medium of GR cells contained seven proteins, identified as gp55, gp33, p25, pp2O, p16, p12, and plO. The major viral phosphoprotein was the 20,000-molecular-weight protein, pp2O. Immunoprecipitation of cytoplasmic extracts from pulse-labeled GR cells identified three MMTV gag-specific proteins, termed Pr78WaF, Prl1110F, and Prl80V'9. These intracellular polyproteins were precipitable from cytoplasmic extracts by antisera to virions p25 and p12 but not by antisera to gp55. The major intracellular gag-specific precursor polyprotein, Pr78gag, contained antigenic determinants and tryptic peptides characteristic of p25, p12, plO, and presumably pp2O. This precursor is presumably derived from nascent chain cleavage or rapid posttranslational cleavage of the larger intracellular precursor-like protein, designated Pr11099. Pr11099 contained all but one of the leucine-containing tryptic peptides of Pr789"9, plus several additional peptides. In addition to Pr78gw and Pr1109`9, monospecific antisera to virion p12 and p25 were also capable of precipitating from pulse-labeled cells a small amount of a 180,000-molecularweight precursor-like protein, designated Prl80gaF. This large polyprotein contained nearly all of the leucine-containing tryptic peptides of Pr789, and Prll0g10 plus several additional peptides. By analogy to type C viral systems, Pr180Y9 is presumed to represent a gag-pol common precursor which is the major pathway for synthesis of MMTV polymerase. Immunoprecipitation of cytoplasmic extracts from pulse-labeled cells with antisera to gp55 identified two env-specific proteins, designated gPr76en" and gp79env. The major env precursor, gPr76en", could be labeled with radioactive glucosamine and was shown to contain antigenic determinants and tryptic peptides characteristic of gp55 and gp33. A minor glycoprotein, gP79env, contained both fucose and glucosamine and was precipitable from cytoplasmic extracts with monospecific serum to gp55. It is suggested that gP79env represents fucosylated gPr76en" which is transiently synthesized and cleaved rapidly into gp55 and gp33.

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“…Recognizing that these individual components result from cleavage of a polyprotein precursor readily explains the known and potential differences in the molecular weight of proteins with the same function in different viruses. Thus, p12 in murine leukemia virus (MuLV) and p l 5 in baboon virus (BaLV) are both phosphoproteins (53) with typespecific antigenicity ( I ) , leading to the prediction that a shift in cleavage site has led to the apparent molecular weight difference (J. Stephenson, personal communication).…”

Section: Products Of the Gag Genementioning

confidence: 99%

“…Group and interspecies determinants are less potent, or may be silent, probably depending on the host and immunization conditions. Antigenically, p l 5 is distinct from other viral structural proteins (7, 26, 57, 6 8 ) , and in some viruses it is phosphorylated (53). On the basis of antigenic properties, it has been suggested that p l 5 may specify the Friend-Moloney-Rauscher subgroup of murine type-C viruses (68).…”

Section: P ' Jmentioning

confidence: 99%