A novel oncogene, v-ryk, encoding a truncated receptor tyrosine kinase is transduced into the RPL30 virus without loss of viral sequences.
The RPL viruses are acute oncogenic avian retroviruses isolated from chicken tumors. We carried out a genetic analysis of three of the viruses, RPL25, RPL28, and RPL30. While RPL25 and RPL28 were shown to contain the erbB oncogene, RPL30 appeared to contain a novel protein tyrosine kinase oncogene. This gene, v-ryk, was cloned and sequenced. The v-ryk oncogene contains a 1.39-kb nonretroviral sequence that includes a tyrosine kinase domain which was inserted into the viral envelope protein gp37-coding region and fused in frame with upstream gp37 to generate a P69gp37-ryk fusion oncoprotein. Unlike that of other acutely transforming retroviruses, transduction of the v-ryk gene into RPL30 did not result in deletion of viral sequences. Sequence analysis suggested that v-Ryk is more homologous to receptor-type tyrosine kinases than to nonreceptor-type kinases. By reconstitution of a virus from its cDNA, the v-ryk oncogene has been shown to be fully responsible for the transforming activity of the RPL30 virus. Antibodies specific to v-Ryk immunoprecipitated the v-Ryk oncoprotein from cells transformed by the RPL30 virus. The v-Ryk protein was shown to be first synthesized as a 150-kDa precursor and then cleaved into the mature 69-kDa gp37-Ryk fusion protein, both parts of which were found to be localized to the membrane fraction. As expected from the sequence of v-Ryk, immunoprecipitates of v-Ryk from RPL30-transformed cells were found to display a protein tyrosine kinase activity in vitro, and the levels of tyrosine-phosphorylated proteins are elevated in v-ryk-transformed cells.
Jia
R
R
Rockefeller University, New York, New York 10021-6399.
Mayer
B J
BJ
Hanafusa
T
T
Hanafusa
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002642:Chick Embryo; D004247:DNA; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics*; D009857:Oncogenes; D010957:Plasmids; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection; D014764:Viral Proteins
D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion; D014764:Viral Proteins; C076739:v-ryk protein, avian retrovirus; D004247:DNA; D011505:Protein-Tyrosine Kinases