Evidence that a cytoplasmically located version of a v-erbB-encoded protein can transform both fibroblasts and erythroblasts.
We previously isolated an avian erythroblastosis virus, AEV-GEE35, in which the complete extracellular and transmembrane domains of the v-erbB oncoprotein were replaced with sequences from the gag and env proteins. The GEE35 virus was capable of transforming both fibroblasts and erythroblasts as efficiently as wild-type v-erbB. Analysis of the v-erbB proteins encoded by GEE35 revealed two proteins of similar molecular weights of approximately 130,000 Da. One of these proteins was an N-linked glycosylated membrane protein, whereas the other was a cytoplasmic protein. Biochemical characterization of these two proteins revealed that the transmembrane protein has the v-erbB domain outside the cell, such that it no longer had access to its tyrosine kinase substrates. This implies that it is the cytoplasmically located v-erbB-encoded protein that is responsible for the efficient transforming ability of this virus.
Department of Microbiology, State University of New York, Stony Brook 11794.
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Lee
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Meyer
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Hayman
D001355:Alpharetrovirus / Q000235:genetics* / Q000502:physiology; D015153:Blotting, Western; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D003593:Cytoplasm / Q000737:chemistry; D004900:Erythroblasts / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D018739:Oncogene Proteins v-erbB; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000502:physiology*; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000502:physiology*
D018739:Oncogene Proteins v-erbB; D009856:Oncogene Proteins, Viral; D015682:Retroviridae Proteins, Oncogenic