Expression of mitogenically active human recombinant platelet-derived growth factor A-chain.
Expression vectors encoding cDNAs for the human platelet-derived growth factor (PDGF) A-chain (pJKl) and murine dihydrofolate reductase (pTKDHFR) were cotransfected into dihydrofolate reductase-deficient Chinese hamster ovary cells. Methotrexate-induced coamplification of clones, expressing PDGF A-chain resulted in enhanced levels of A-chain-specific DNA, RNA and protein. A 30,500 Mr protein was immunoprecipitated with PDGF antisera from the conditioned media of metabolically labeled cells. Reducing conditions resolved the A-chain-specific protein into two polypeptides of 16,500 and 17,000 Mr, confirming the homodimeric nature of the recombinant A-chain protein. The recombinant PDGF A-chain produced constitutively by these amplified clones proved to be mitogenically active. The secretion of a recombinant PDGF A-chain into conditioned media may provide a continuous and abundant source of PDGF A.A dimers, normally produced by specific tissues in only minute quantities. Future purification of the recombinant homodimeric A-chain will allow the assessment of its ability to function in clinical applications such as wound healing.
Kaplow
J M
JM
Rorer Biotechnology, Inc., King of Prussia, PA 19406.
Tong
B D
BD
Hurwitz
D R
DR
Jaye
M
M
D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005784:Gene Amplification; D015870:Gene Expression; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology*; D010957:Plasmids; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D012313:RNA / Q000302:isolation & purification; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis; D013762:Tetrahydrofolate Dehydrogenase / Q000096:biosynthesis
D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; D012313:RNA; D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate