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Nucleotide sequence of v-fps in the PRCII strain of avian sarcoma virus
Abstract:
PRCII is an avian retrovirus whose oncogene (v-fps) induces fibrosarcomas in birds. The viral gene v-fps arose by transduction of an undetermined portion of a cellular gene known as c-fps. PRCII is weakly oncogenic when compared with Fujinami sarcoma virus, another transforming virus containing v-fps. As a first step in the elucidation of the molecular basis for the decreased virulence of PRCII, we have determined the entire nucleotide sequence of v-fps in the PRCII genome. The v-fps domain in PRCII encodes a polypeptide with a molecular weight of ca. 60,500 fused to a portion of the polyprotein encoded by the viral structural gene gag. The hybrid gag-fps polyprotein of PRCII would have a molecular weight of ca. 98,100, in accord with results of previous studies of the protein encoded by the PRCII genome. The leftward junctions between fps and gag in Fujinami sarcoma virus and PRCII are located at the same position in fps, but at different positions in gag. A sequence of 1,020 nucleotides, bounded by direct repeats of 6 nucleotides, is present in v-fps of Fujinami sarcoma virus but absent from PRCII. Our data should permit further explorations of the relationship between structure and function in the transforming protein encoded by v-fps.
Insights
Researchers sequenced the v-fps oncogene in PRCII avian retrovirus. A 1,020-nucleotide sequence present in Fujinami sarcoma virus is absent in PRCII, explaining its weaker fibrosarcoma-inducing ability.
Area of Science:
- Molecular biology
- Virology
- Oncology
Background:
- PRCII is an avian retrovirus encoding the v-fps oncogene, which causes fibrosarcomas.
- v-fps originates from a cellular gene, c-fps.
- PRCII exhibits lower oncogenicity compared to Fujinami sarcoma virus, which also contains v-fps.
Purpose of the Study:
- To investigate the molecular basis for PRCII's reduced virulence.
- To determine the complete nucleotide sequence of the v-fps gene within the PRCII genome.
Main Methods:
- Nucleotide sequencing of the v-fps gene in the PRCII genome.
- Comparison of the PRCII v-fps sequence with that of Fujinami sarcoma virus.
Main Results:
- The v-fps domain in PRCII encodes a 60,500 MW polypeptide fused to the gag polyprotein, forming a 98,100 MW hybrid.
- The gag-fps junctions in PRCII and Fujinami sarcoma virus differ in the gag region.
- A 1,020-nucleotide sequence, flanked by direct repeats, is present in Fujinami sarcoma virus's v-fps but absent in PRCII's.
Conclusions:
- The absence of a specific 1,020-nucleotide sequence in PRCII's v-fps gene is a key difference contributing to its decreased oncogenic potential.
- These findings provide a foundation for understanding the structure-function relationship of the v-fps transforming protein.