Expression of the oncogene of avian reticuloendotheliosis virus in Escherichia coli and identification of the transforming protein in reticuloendotheliosis virus T-transformed cells.
The genome of reticuloendotheliosis virus T (REV-T) includes a unique oncogene v-rel, which is transcribed in low amounts into a 3.0-kilobase subgenomic mRNA in REV-T-transformed lymphoid cells. To identify the v-rel protein, REV-T DNA sequences were cloned into bacterial plasmid vectors designed to achieve expression of foreign DNA sequences in Escherichia coli. Portions of the v-rel gene were joined to the 5' segment of the trpE gene. Upon induction of trpE with indoleacrylic acid, large amounts of trpE-v-rel fusion proteins were produced by the bacteria carrying these recombinant plasmids. Two trpE-v-rel fusion proteins were synthesized in E. coli, which collectively represent three-quarters of the predicted v-rel protein. Polyclonal antisera were generated to trpE-v-red fusion proteins. These antisera were used in immunoblotting experiments to identify a 57-kDa v-rel protein in REV-T-transformed lymphoid cells lines and REV-T-infected chicken embryo fibroblast cultures. The v-rel gene expressed in E. coli under lac control was found to produce a 56-kDa protein. Although REV-T-transformed and Marek disease virus-transformed lymphoid cells contain c-rel mRNA transcripts, a c-rel protein could not be detected with antisera directed against v-rel fusion proteins.
D000818:Animals; D002472:Cell Transformation, Viral; D002645:Chickens; D004274:DNA, Recombinant / Q000378:metabolism; D004331:Drosophila melanogaster; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D009857:Oncogenes; D010957:Plasmids; D011817:Rabbits; D001356:Reticuloendotheliosis virus / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics*
D004274:DNA, Recombinant