Premium
The B chain of PDGF alone is sufficient for mitogenesis.
Author(s) -
Kelly J.D.,
Raines E.W.,
Ross R.,
Murray M.J.
Publication year - 1985
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1985.tb04096.x
Subject(s) - biology , heterologous , genetics , gene
The platelet‐derived growth factor (PDGF) is a mitogen derived from human platelets consisting of two related polypeptides termed A and B chains. The entire B chain of PDGF is highly (96%) homologous to a portion of p28sis, the transforming protein of simian sarcoma virus. It has been suggested that p28sis exerts its transforming potential by mimicking the growth promoting activity of PDGF and stimulating the cell in an autocrine manner. We have directly examined the mitogenic potential of p28sis and the B chain homologous region by expressing these heterologous sequences in the yeast Saccharomyces cerevisiae. In our constructions, these proteins are encoded by portions of the v‐sis gene. Expression and secretion from the yeast cell is achieved by using a yeast promoter and the alpha‐factor pheromone secretory leader. The sis proteins thus expressed and secreted are immunoreactive with anti‐PDGF antisera and are mitogenic for cultured fibroblasts. Furthermore, they mediate this mitogenic activity by specific binding to the PDGF cell surface receptor. Gel electrophoresis and cell binding analysis indicates that the mitogenic species is primarily a disulphide‐bonded dimer. We are able to conclude that p28sis is a mitogen and that a polypeptide corresponding to the B chain alone is sufficient to account for the mitogenic activity attributed to PDGF.