Expression of the c-erbB-2 protein in normal and transformed cells.
Two synthetic peptides from the predicted sequence of the human c-erbB-2 protein were synthesized and used to raise antisera in rabbits. The sequences chosen were identical to those in the homologous rat c-neu protein. The antibodies produced reacted with the immunizing peptides in ELISA but showed little or no cross-reaction with the partly homologous peptides found in equivalent positions in the human EGF receptor. Both antipeptide antibodies, and a monoclonal antibody (MAb) specific for the rat neu protein, immunoprecipitated a 185-kDa protein from 35S-methionine-labelled lysates prepared from a rat cell line known to express high levels of the c-neu protein. The antipeptide antibodies also recognized a protein of the same size in Western blots. In addition, both antipeptide antibodies immunoprecipitated a 190-kDa protein from labelled cell lysates prepared from human and monkey cells. Antibodies to one of the peptides, which showed no detectable cross-reaction with human, rat or monkey EGF receptor, were used to examine the expression of the c-erbB-2 protein on a variety of cultured cell types. Eleven transformed, I non-established and 2 immortalized cell types were examined by immunoprecipitation for their level of expression of the c-erbB-2 protein and of the EGF receptor. The numbers of EGF receptors varied widely between different cell lines, whereas the level of the c-erbB-2 protein, which was found on all of the cell types examined, was more constant. The number of c-erbB-2 molecules present was estimated by autoradiography to be about 100,000 per cell. The antibodies were then used to examine the location and level of expression of the human c-erbB-2 and rat c-neu proteins in normal tissues. Immunohistochemical staining showed that the c-erbB-2 protein was highly expressed in rat kidney proximal tubules and loop of Henle. The c-erbB-2 protein was also present on normal human epithelial cells but in some cases with a different distribution to that of the EGF receptor.
Gullick
W J
WJ
Berger
M S
MS
Bennett
P L
PL
Rothbard
J B
JB
Waterfield
M D
MD
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D066246:ErbB Receptors / Q000032:analysis; D005784:Gene Amplification; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007668:Kidney / Q000032:analysis; D009061:Mouth Mucosa / Q000032:analysis; D009369:Neoplasms / Q000032:analysis*; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000276:immunology; D011817:Rabbits; D051381:Rats; D014513:Ureter / Q000032:analysis
D007106:Immune Sera; D011518:Proto-Oncogene Proteins; D066246:ErbB Receptors