A β-type transforming growth factor, present in conditioned cell culture medium independent of cell transformation, may derive from serum

✍ Scribed by Kurt Stromberg; Daniel R. Twardzik

• Book ID: 102301939
• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 336 KB
• Volume: 27
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240270412

✦ Synopsis

An alpha-type transforming growth factor (TGF,) is produced at high levels by rat embryo cells transformed by the Snyder-Theilen strain of feline sarcoma virus (FeSV). Addition of 2 ng mouse epidermal growth factor (mEGF) during purification identified the presence of a second, EGF-dependent growth factor of the TGF beta type (TGF,) in this conditioned medium. This factor had an approximate Mr of 12,000 and eluted at 37% acetonitrile during high performance liquid chromatography. This extracellular type of TGF, activity also was present in conditioned medium of rat cells after infection with a transformation defective strain of Abelson leukemia virus, and hence expression of this growth factor activity was independent of cell transformation. Moreover, the presence of an EGF-dependent, 12,000 Mr clonogenic activity in extracts of bovine serum alone suggests serum as an origin for the B-type transforming growth factor initially observed in conditioned medium of Snyder-Theilen FeSV transformed cells. This does not, however, preclude the possibility that TGF, is also secreted by the transformed rat embryo cells themselves.