The growth inhibitor of African green monkey (BSC-1) cells is transforming growth factors beta 1 and beta 2.
The growth inhibitory activity in conditioned medium of African green monkey kidney epithelial (BSC-1) cells that has been shown to arise, at least in part, from transforming growth factor beta 2 (TGF-beta 2) [Hanks, S. K., Armour, R., Baldwin, J. H., Maldonado, F., Spiess, J., & Holley, R. W. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 79-82] was tested for growth inhibitory activity prior to and following acidification. Similar to TGF-beta 1 from human platelets, the inhibitory activity from BSC-1 cells demonstrated an 8-10-fold stimulation following acidification, showing that the activity was secreted from the cells in latent form. Conditioned medium from BSC-1 cells was collected, acidified, and fractionated by procedures that separate TGF-beta 1 and -2. Biological activity was assayed by using the BSC-1 cell proliferation assay. Two active proteins with properties similar to known TGF-beta 1 and TGF-beta 2 were identified. Identity was confirmed by using immunological and amino acid sequencing techniques. These results were consistent with Northern blot analysis of total BSC-1 RNA, using cDNA probes for TGF-beta 1 and TGF-beta 2, which demonstrated strong signals for both mRNAs. Metabolic labeling in conjunction with two-dimensional gel electrophoresis revealed that the cells secrete approximately 10% TGF-beta 1 and 90% TGF-beta 2.
McPherson
J M
JM
Celtrix Laboratories, Collagen Corporation, Palo Alto, California 94303.
Sawamura
S J
SJ
Ogawa
Y
Y
Dineley
K
K
Carrillo
P
P
Piez
K A
KA
D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002522:Chlorocebus aethiops; D015342:DNA Probes; D006131:Growth Inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D015291:Transforming Growth Factors / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification
D015342:DNA Probes; D006131:Growth Inhibitors; D015291:Transforming Growth Factors