p59v-rel, the transforming protein of reticuloendotheliosis virus, is complexed with at least four other proteins in transformed chicken lymphoid cells.
Previous studies have identified the protein product of v-rel, the oncogene carried by reticuloendotheliosis virus (REV), as a 59,000-dalton phosphoprotein located predominantly in the cytosol of transformed chicken lymphoid cells. In immune precipitates of p59v-rel, there is a closely associated protein kinase activity. In chicken lymphoid cells that do not contain REV, p68c-rel is found free in the cytosol not associated with other proteins and not detectably phosphorylated. In this study, we found that immune precipitates of 59v-rel from REV-transformed cells contain at least four other proteins, of approximate molecular weights 124, 115, 68, and 36 kilodaltons (kDa). The 124-, 115-, and 36-kDa proteins are apparently unrelated to p59v-rel in sequence, and their coprecipitation suggests that they are complexed with p59v-rel. The coprecipitating 68-kDa protein was found to be p68c-rel, which, like the other three proteins, precipitates by virtue of its association with p59v-rel. Glycerol gradient analysis suggested the presence of more than one type of complex: one containing p115, p68c-rel, p59v-rel, and p36, and another containing p124, p115, p59v-rel, and possibly p68c-rel. In vitro kinase activity was found in all size classes, coinciding with the distribution of p115 and p59v-rel. The complex(es) was stable under a variety of conditions, including a wide range of ionic strengths, chelators, and detergents, and through multiple cycles of immune precipitation and elution. This suggests a specific and functionally significant interaction among the members that may be of direct relevance to the mechanism of REV-induced transformation.
Simek
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Laboratory of Molecular Virology and Carcinogenesis, Bionetics Research, Incorporated, Frederick, Maryland 21701.
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D000818:Animals; D002461:Cell Line, Transformed; D002499:Centrifugation, Density Gradient; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera; D008221:Lymphoid Tissue / Q000166:cytology; D020572:Oncogene Proteins v-rel; D011233:Precipitin Tests; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020569:Proto-Oncogene Proteins c-rel; D001356:Reticuloendotheliosis virus; D012190:Retroviridae; D012191:Retroviridae Proteins / Q000378:metabolism*
D007106:Immune Sera; D020572:Oncogene Proteins v-rel; D011506:Proteins; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D012191:Retroviridae Proteins; D011494:Protein Kinases