Insulin/insulin-like growth factor I induce actin transcription in mouse fibroblasts expressing constitutively myc gene.
Quiescent benzo[alpha]pyrene-transformed BALB/c 3T3 fibroblasts (line BP-A31), continue to express 'competence' genes (such as c-myc) and do not require platelet-derived growth factor ('competence' factor) in order to resume the cell division cycle. Insulin-like growth factor I (IGF-I), as well as insulin (at high concentrations, where it interacts with IGF-I-receptors) are potent mitogens in these cells. In contrast with the original non-transformed A31 cell line, we show that insulin/IGF-I (even in the absence of de novo protein synthesis) induce actin transcription in BP-A31 cells. We have verified that 'CArG' boxes, major actin promoter elements, can act as insulin-inducible elements in BP-A31 cells. Insulin-induced actin transcription is also observed in quiescent A31 cells stably transfected with a myc expression vector, suggesting a correlation between constitutive myc expression and insulin-induced actin transcription.
Buchou
T
T
INSERM U 55, Hôpital St-Antoine, Paris, France.
Gaben
A M
AM
Phan-Dinh-Tuy
F
F
Mester
J
J
D000199:Actins / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002461:Cell Line, Transformed; D003001:Cloning, Molecular; D004247:DNA; D015870:Gene Expression; D016259:Genes, myc; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D017451:Receptors, Somatomedin; D014158:Transcription, Genetic; D014162:Transfection
D000199:Actins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D004247:DNA