Expression of the c-sis gene and secretion of a platelet-derived growth factor-like protein by simian virus 40-transformed BHK cells.

SV40-transformed BHK cells were shown to express two transcripts, of 3.5 kb and 2.0 kb, that hybridised to a human c-sis probe. Antibodies directed against human PDGF specifically recognized a 31 kDa protein in SV40/BHK cell conditioned medium, which upon reduction was split into 16 kDa species. Unfractionated conditioned medium and one of two growth factors isolated from SV40/BHK cells competed with 125I-PDGF for binding to its receptor. The present communication thus provides compelling evidence that an SV40/BHK cell-derived growth factor is a hamster equivalent to human PDGF.