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Cholera toxin potentiates TPA‐induced mitogenesis and c‐ fos expression in BALB/c‐3T3‐derived proadipocytes
Author(s) -
Smyth Miriam J.,
Runnels Beth,
Wharton Walker
Publication year - 1992
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240500211
Subject(s) - cholera toxin , forskolin , toxin , stimulation , cholera , endocrinology , biology , medicine , insulin , chemistry , biochemistry , microbiology and biotechnology
Treatment of quiescent density‐arrested A31T6 proadipocytes with medium supplemented with either 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), insulin, or cholera toxin alone did not simulate G 0 /G 1 traverse and initiation of DNA synthesis. Combinations of either TPA and cholera toxin or insulin and cholera toxin caused a small stimulation of proliferation. Addition of medium supplemented with TPA and insulin caused a marked stimulation of cell cycle traverse which was significantly potentiated by the coaddition of cholera toxin. The actions of cholera toxin were mimicked by forskolin. Expression of c‐ fos was regulated in a manner that reflected the results of the mitogenic experiments. TPA caused a marked induction of expression, while only a small increase in transcript levels was seen after treatment with cholera toxin. Addition of a combination of cholera toxin and TPA caused a synergistic induction of c‐ fos expression. The model system described in this paper allows a detailed analysis of the regulation, by independent second messenger system, of the transcription of a gene in a mitogenically relevant manner. © 1992 Wiley‐Liss, Inc.